Items & Mobiles

This guide covers the most common content creation tasks: building items and creatures for your shard.

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Creating an Item

Minimal Item

Every item needs [SerializationGenerator], a partial class, and a [Constructible] constructor:

using ModernUO.Serialization;

namespace Server.Items;

[SerializationGenerator(0)]
public partial class SimpleItem : Item
{
    [Constructible]
    public SimpleItem() : base(0x1234)
    {
        Weight = 1.0;
    }

    public override string DefaultName => "a simple item";
}

• 0x1234 is the item graphic ID from UO art files.
• DefaultName sets the tooltip name. Use LabelNumber for cliloc-based names instead.

Full Item Example

A complete item with serialized fields, a timer, property list, and double-click behavior:

using ModernUO.Serialization;

namespace Server.Items;

[SerializationGenerator(0)]
public partial class MagicLantern : Item
{
    [SerializableField(0)]
    [InvalidateProperties]
    [SerializedCommandProperty(AccessLevel.GameMaster)]
    private int _charges;

    [SerializableField(1)]
    [SerializedCommandProperty(AccessLevel.GameMaster)]
    private Mobile _owner;

    private TimerExecutionToken _glowTimer;

    [Constructible]
    public MagicLantern() : base(0xA25)
    {
        _charges = Utility.RandomMinMax(5, 15);
        Weight = 2.0;
        Light = LightType.Circle300;
        StartGlow();
    }

    public override string DefaultName => "a magic lantern";

    private void StartGlow()
    {
        Timer.StartTimer(TimeSpan.FromSeconds(3), TimeSpan.FromSeconds(3), Glow, out _glowTimer);
    }

    [AfterDeserialization]
    private void AfterDeserialization() => StartGlow();

    public override void OnAfterDelete()
    {
        _glowTimer.Cancel();
        base.OnAfterDelete();
    }

    private void Glow()
    {
        if (_charges > 0)
        {
            Effects.SendLocationParticles(this, 0x376A, 9, 10, 5042);
        }
    }

    public override void OnDoubleClick(Mobile from)
    {
        if (!IsChildOf(from.Backpack))
        {
            from.SendLocalizedMessage(1042001); // Must be in your backpack
            return;
        }

        if (_charges <= 0)
        {
            from.SendMessage("The lantern is depleted.");
            return;
        }

        Charges--;
        from.SendMessage("The lantern flares brightly!");
        from.FixedParticles(0x376A, 9, 32, 5042, EffectLayer.Waist);
    }

    public override void GetProperties(IPropertyList list)
    {
        base.GetProperties(list);
        list.Add(1060741, $"{_charges}"); // "charges: ~1_val~"
    }
}

Key patterns:

• TimerExecutionToken is never serialized -- restart it in [AfterDeserialization].
• [InvalidateProperties] auto-refreshes the tooltip when Charges changes.
• [SerializedCommandProperty] exposes the field to the [Props gump for GMs.
• OnAfterDelete cancels the timer to prevent it firing on a deleted entity.

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Common Base Classes

Base Class	Use For
Item	Generic items
BaseWeapon	Melee weapons
BaseRanged	Ranged weapons (bows, crossbows)
BaseArmor	Armor pieces
BaseShield	Shields
BaseClothing	Wearable clothing
BaseJewel	Rings, bracelets, necklaces
BaseContainer	Containers (bags, boxes, chests)
BasePotion	Potions
Food	Edible items
SpellScroll	Spell scrolls

---

Key Item Properties

Set these in the constructor:

Weight = 1.0;                    // Weight in stones
Stackable = true;                // Can stack with same type
Amount = 1;                      // Stack amount
Movable = true;                  // Can be picked up
Hue = 0;                         // Color (0 = default)
LootType = LootType.Regular;     // Regular, Newbied, Blessed, Cursed
Layer = Layer.OneHanded;         // Equipment layer
Light = LightType.Circle300;     // Light emission

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Creating a Creature

Basic Creature

Creatures extend BaseCreature and define stats, resistances, skills, and loot:

using ModernUO.Serialization;
using Server.Items;

namespace Server.Mobiles;

[SerializationGenerator(0)]
public partial class ForestWolf : BaseCreature
{
    [Constructible]
    public ForestWolf() : base(AIType.AI_Melee, FightMode.Closest)
    {
        Body = 225;
        BaseSoundID = 0xE5;

        SetStr(80, 120);
        SetDex(90, 110);
        SetInt(20, 40);

        SetHits(60, 80);
        SetMana(0);

        SetDamage(8, 14);

        SetDamageType(ResistanceType.Physical, 100);

        SetResistance(ResistanceType.Physical, 25, 35);
        SetResistance(ResistanceType.Fire, 5, 10);
        SetResistance(ResistanceType.Cold, 15, 25);
        SetResistance(ResistanceType.Poison, 10, 15);
        SetResistance(ResistanceType.Energy, 5, 10);

        SetSkill(SkillName.MagicResist, 30.0, 50.0);
        SetSkill(SkillName.Tactics, 50.0, 70.0);
        SetSkill(SkillName.Wrestling, 50.0, 70.0);

        Fame = 600;
        Karma = 0;

        VirtualArmor = 28;

        Tamable = true;
        ControlSlots = 1;
        MinTameSkill = 50.1;
    }

    public override string CorpseName => "a wolf corpse";
    public override string DefaultName => "a forest wolf";
    public override int Meat => 1;
    public override int Hides => 6;
    public override HideType HideType => HideType.Regular;
    public override FoodType FavoriteFood => FoodType.Meat;
    public override PackInstinct PackInstinct => PackInstinct.Canine;

    public override void GenerateLoot()
    {
        AddLoot(LootPack.Meager);
    }
}

Optional Creature Overrides

public override Poison PoisonImmune => Poison.Regular;
public override Poison HitPoison => Poison.Lesser;
public override double HitPoisonChance => 0.2;
public override bool CanRummageCorpses => true;
public override bool BardImmune => true;
public override bool Unprovokable => true;
public override bool CanFly => true;
public override int TreasureMapLevel => 3;
public override double WeaponAbilityChance => 0.4;

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AI Types

AIType	Use For
AI_Melee	Warriors, melee fighters
AI_Mage	Spellcasters
AI_Archer	Ranged attackers
AI_Animal	Passive animals (flee when hurt)
AI_Predator	Hunting animals
AI_Healer	Healing NPCs
AI_Vendor	Shop NPCs

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Fight Modes

FightMode	Behavior
None	Never attacks
Aggressor	Only retaliates when attacked
Strongest	Targets highest-stat enemy
Weakest	Targets lowest-stat enemy
Closest	Targets nearest enemy
Evil	Attacks aggressors or evil-karma targets

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Creature Stats Guide

Use these ranges as a baseline when creating creatures:

Level	Str	Dex	Int	Hits	Damage	Fame
Weak	30--60	30--50	10--20	20--40	2--6	100--300
Average	80--120	60--90	20--40	60--100	6--14	500--1,500
Strong	150--250	80--120	50--100	120--200	12--22	2,000--5,000
Elite	300--500	100--150	100--200	250--500	18--30	5,000--15,000
Boss	500--1,000	150--250	200--400	500--2,000	25--40	15,000+

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Loot System

Predefined Loot Packs

Use AddLoot in GenerateLoot() to assign standard loot tiers:

public override void GenerateLoot()
{
    AddLoot(LootPack.Poor);         // ~50 gold equivalent
    AddLoot(LootPack.Meager);       // ~100 gold equivalent
    AddLoot(LootPack.Average);      // ~250 gold equivalent
    AddLoot(LootPack.Rich);         // ~500 gold equivalent
    AddLoot(LootPack.FilthyRich);   // ~1,000 gold equivalent
    AddLoot(LootPack.UltraRich);    // ~2,000 gold equivalent
    AddLoot(LootPack.SuperBoss);    // Boss-level loot

    // Auxiliary packs
    AddLoot(LootPack.Gems, 2);      // 2 random gems
    AddLoot(LootPack.Potions);      // Random potion
    AddLoot(LootPack.LowScrolls);   // Circle 1--4 scroll
    AddLoot(LootPack.MedScrolls);   // Circle 5--6 scroll
    AddLoot(LootPack.HighScrolls);  // Circle 7--8 scroll
}

Packs automatically select era-appropriate loot based on the server expansion.

Specific Items

For items that always drop, add them directly:

PackItem(new Arrow(Utility.RandomMinMax(20, 40)));
PackGold(100, 200);
PackItem(new Bandage(Utility.RandomMinMax(5, 10)));

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Property Lists (Tooltips)

Override GetProperties to customize what players see when hovering over your item:

public override void GetProperties(IPropertyList list)
{
    base.GetProperties(list); // Always call base first

    // Cliloc with a value argument
    list.Add(1060741, $"{_charges}");             // "charges: ~1_val~"

    // Key-value pair (string constants must be holes)
    list.Add(1060658, $"{"Quality"}\t{_quality}"); // "~1_val~: ~2_val~"

    // Raw string line
    list.Add($"{"Crafted with care"}");
}

warning

String literals in interpolated property list arguments must be wrapped as holes: $"{"Map"}\t{value}" not $"Map\t{value}". The handler treats bare text as delimiters and {} holes as arguments. Only \t should be a bare literal.

Use [InvalidateProperties] on serialized fields to auto-refresh tooltips when values change.

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Entity Lifecycle

Entities go through a two-phase deletion process:

// Phase 1: Pre-removal -- cancel timers, unregister from systems
public override void OnDelete()
{
    _timerToken.Cancel();
    base.OnDelete();
}

// Phase 2: Post-removal -- null out references
public override void OnAfterDelete()
{
    _timer?.Stop();
    _timer = null;
    _owner = null;
    base.OnAfterDelete();
}

Phase	Method	What to Do
Pre-removal	OnDelete()	Cancel TimerExecutionToken, unregister from tracking systems
Post-removal	OnAfterDelete()	Stop and null Timer references, null Item/Mobile references

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File Organization

Place new content files under Projects/UOContent/ following this structure:

Projects/UOContent/
  Items/
    Weapons/Swords/          # Swords
    Weapons/Maces/           # Maces
    Weapons/Ranged/          # Bows, crossbows
    Armor/Plate/             # Plate armor
    Armor/Leather/           # Leather armor
    Clothing/                # Wearable clothing
    Containers/              # Bags, boxes, chests
    Misc/                    # General items
    Special/                 # Unique or quest items
    Resources/               # Crafting materials
  Mobiles/
    Animals/Bears/           # Bears
    Animals/Birds/           # Birds
    Monsters/AOS/            # AOS-era monsters
    Monsters/SE/             # SE-era monsters
    Monsters/ML/             # ML-era monsters
    Special/                 # Champions, bosses
    Vendors/                 # NPC vendors
    Townfolk/                # NPCs

Naming rules:

• File name matches the primary class name.
• One primary class per file.
• Group related items in subdirectories.
• Era-specific content goes in era-named subdirectories.