Abilities

Spells and attacks run on the server, so this works for players without Kiln. The exception: a key binding needs Kiln and your mod on that player’s game. Chat commands and server triggers need nothing.

A new ability

Abilities.Register(new AbilityDefinition
{
    Id = "firenova:fire-nova", DisplayName = "Fire Nova",
    DefaultKey = "G", ChatCommand = "nova",
    Cost = AbilityCost.OfMana(40), Cooldown = TimeSpan.FromSeconds(5),
    Targeting = AbilityTargeting.Self,
    OnCast = async cast =>
    {
        await cast.Impact("Explosion_Player_Spell_Fireball_1", cast.CasterPosition,
            new ImpactConfigs { ["Damage1"] = DamageSetup.FireOnly(10f) });
    },
});

Register it in a side: both mod. Players remap keys in the Kiln menu. /cast <id> and ChatCommand work for everyone. Abilities.Cast(actor, id) casts from code, for players, creatures or NPCs. Kiln checks the cooldown, cast lock, target and cost, then runs OnCast on the server.

An explosion you run yourself has no weapon behind it. Give it its own damage (Damage1 above), or it hits for 0.

Change the game’s spells, per cast

[Subscribe]
private void OnImpact(ImpactStartingEvent e)
{
    if (e.RootIsPlayer && IsNight()
        && e.TemplateName?.StartsWith("Explosion_Player_Spell_Fireball") == true)
        e.Scale("AttackMod", 2f);           // or e.Set(...), or e.Cancel()
}

Abilities.HoldPrograms(...) limits this to the effects you care about. For the same change every cast, use game data.

Run effects, buffs and animations

await Abilities.RunImpact("Explosion_Player_Spell_Fireball_1", position,
    new ImpactOptions { Root = caster });
await Abilities.ApplyBuff(target, buffGuid, TimeSpan.FromSeconds(6), caster);
Abilities.PlaySequence(player, emoteGuid, SequenceOptions.Queue);
int? mana = Abilities.Attributes.Get(player, AbilityResource.Mana);

PlaySequence plays the game’s actions (a swing, an emote) on a player, NPC or creature. A cast played this way shows its animation but doesn’t fire the spell.

Watch and adjust hits

ImpactDamageEvent, ImpactBuffEvent and ImpactSpawnEvent report what spells did. Abilities.OnDamage can change one hit.

New gameplay logic

When values aren’t enough, write an Impact program.