Building a Custom Boss

What it is and who it's for

A Custom Boss lets your group build a boss encounter yourself: its phases and its ability timers. Once it exists, you plan cooldowns on it exactly like any built-in boss, with the same timeline, the same drag-and-drop, and the same exports.

It's made mainly for the very top end of the race, the guilds pushing ahead of our built-in timers in the early days of a tier, or anyone who wants to model a fight on their own terms before we've refined it. You can also use it to plan an encounter we don't cover.

It stays private to your group

A custom boss lives with your group and nobody else. It isn't shared with other groups, and nothing about it is sent to us. You can plan a fight entirely on your own terms, well before anyone else sees your read on it.

Before you start

You turn the feature on per group, then anyone with Officer access can manage bosses.

Create a boss

In the Custom Bosses card, click Add Custom Boss. You'll get an editor with the encounter JSON on the left and a live preview on the right that updates as you type.

The shape

A boss is one object with a phases array, and each phase has a bossSpellsUsed array. Here's a trimmed version with one phase and one ability:

{
  "bossName": "My Custom Boss",
  "fightEnd": 360,
  "phases": [
    {
      "phaseNumber": 0,
      "phaseTimer": 0,
      "phaseName": "P1",
      "phaseMaxDuration": 120,
      "phaseTimerEditable": false,
      "bossSpellsUsed": [
        {
          "spell": {
            "spellId": 421636,
            "spellName": "Typhoon",
            "wowheadLink": "https://www.wowhead.com/spell=421636/typhoon",
            "iconLink": "https://wow.zamimg.com/images/wow/icons/large/ability_druid_typhoon.jpg"
          },
          "bossSpellType": "Raid AOE",
          "dynamicTimer": [15, 45, 75, 105]
        }
      ]
    }
  ]
}

Add more phases and more abilities the same way. There's also a built-in Custom Boss Example in your boss list you can open and study on the timeline to see how the different ability types render.

The fields that matter

Most fields read plainly. These are the few worth calling out:

A couple of things that trip people up:

• Every ability needs an icon. Point iconLink at a public Wowhead icon, like https://wow.zamimg.com/images/wow/icons/large/ability_druid_typhoon.jpg. Open the spell on Wowhead to find its icon name. Our own boss icons sit on internal paths you can't link to, so use Wowhead's.
• Spell IDs aren't checked against the live game. Any number works, so you can plan with placeholder abilities before real IDs exist. The wowheadLink is optional and just for convenience.

Plan and export with it

Your custom boss shows up right alongside the built-in bosses. Open it and you get the full planner: the timeline, drag cooldowns into place, assign by spec, and export to NSRT (the primary in-game export) or render an MRT note. It behaves like any other boss, because to the planner it is one.

You can also map a custom boss to a Warcraft Logs boss in Compare, so you can review real pulls against the timeline you built.

Good to know

• Cooldowns are current retail only. You can model any encounter, even an older or Classic fight, but the cooldowns you assign come from today's retail specs and classes. That limits non-retail planning for now. If this matters to you, tell us.
• Self-serve by design. We keep the feature running, but we don't build bosses for groups. The live preview and the shape in this guide are everything you need to get it right.
• Deleting a boss is permanent. Any cooldown assignments you made on it stay saved but can no longer be reached once the boss is gone, so delete with care.

Tell us what you'd use it for

This feature exists because a handful of guilds asked for it, and it gets better the same way. If you're planning ahead of our timers, modeling something we don't cover, or wishing it did more, let us know on the Viserio Discord or through the Feedback page.