OSRS Boss Gear & Inventories

Yama

Combat level 1238 · 2500 hitpoints

The Chasm of Fire demon boss. Three phases plus a Judge of Yama sub-fight. Drops the Oathplate armour set, Emberlight components, Purging staff and Soulflame horn.

Requirements

• A Kingdom Divided
• Attack 80+, Strength 80+, Defence 75+
• Prayer 70+ (melee) or 77+ (magic)
• Magic 82+ for Dark Demonbane

Pointers

• Phases 1-2: stand on the MATCHING GLYPH to negate his special attacks. This is the core mechanic. Learn the glyph colours.
• Void flares spawn and must be destroyed before they explode. A Purging staff is purpose-built for this.
• Judge of Yama: you hop across lava stones. MAGIC IS MANDATORY here. It always guarantees a max hit against the Judge.
• Phase 3: Yama stays centred. Dodge the shadow crashes (fireballs travelling in lines), and void flares now spawn at half health.
• Phase 3 melee attacks PIERCE PRAYER for up to 22. Protection prayers are not a solution, positioning is.
• Bring an Elder maul and Soulflame horn for defence reduction, and a Saradomin godsword for healing during the Judge.
• He is a demon. Emberlight/Arclight and Dark Demonbane both apply.

What the sim brings here

Every worn slot and every inventory row below is the combat simulation's own output, at the style it ranks fastest for each account tier. Each line carries the channel that chose it: sim means the model solved it, and inherited means the value came through from the hand-authored loadout the solver starts from. Riding through a generator does not make a value derived, so those are marked rather than presented as the model's answer. A line marked unattributed carries a channel the model's own vocabulary no longer declares, so no word is put on it at all rather than one being read off the channel's spelling. Where the model has not answered a row, its own refusal is printed instead; where it has answered a row it doubts, the answer is printed with the doubt attached rather than withheld.

What each of those badges means

• derived:ascent (sim): an accepted coordinate-ascent move: betterThan() preferred this candidate over the incumbent under the row objective and band. The weapon+ammo+shield pairing and the crystal set arrive here too, because both are offered to the same acceptance test.
• derived:cheapestEqual (sim): cheapestOfEquals(): at budget, an exactly-tied cheaper item replaced the one in this slot. It changes the price and, by construction, not the score.
• derived:composed (sim): balanceInventory() sized this row from the derived supply menu. The menu enumerates CONSUMABLES and narrows by style, tier and price; it is not the authored bag.
• derived:empty (sim): the finished loadout leaves this slot EMPTY, and that is an ANSWER rather than a gap: a two-handed weapon forfeits the shield and a weapon that stores its own ammunition frees the ammo slot. Recorded so a null slot is never read as unprovenanced.
• derived:obtainable (sim): canonicaliseObtainable(): the finished loadout named a variant the model cannot state a route to, and this pass swapped it for the obtainable equal.
• derived:seedWeapon (sim): the weapon the ascent BEGAN from, taken off the dps-ranked weapon shortlist, or the forced weapon of a multi-start seed. Never off a start loadout.
• derived:spec (sim): a carried special-attack weapon PROPOSED by `specPlan` (specchoice.js), which prices every SPEC_ATTACKS weapon that deals damage or drains defence on top of the bag solved without one, and KEPT by `judgeSpecArms` only where the composed bag with it beats the bag without it under `compareScores`. The row's `kpt.specWeapon` carries both arms.
• derived:travel (sim): travelPlan(): the way IN, ranked out of the derived transport graph against this account's own unlocks, rather than copied from whatever a human typed. The way OUT is a separate channel (`ruled:escape`) because it is a typed choice, not a ranking.
• ruled:escape (ruled): escapeLeg(): the way OUT, taken from the typed per-tier table ESCAPE_PLAN and judged against the account, with nothing substituted and no fallback ladder. The ACCOUNT CHECK is a derivation; the CHOICE of item is not, so this is not a `derived:` channel. ESCAPE_PLAN carries no attributedTo field (PROVENANCE_BACKLOG: silent-and-unattributed), so this channel does not claim one either.

Yama strategies on the OSRS Wiki