BEAST/REINCARNATION GUIDE
Language▼

Home / Ursa Boss Guide

Boss guide · Chapter 10

Ursa: Cashing In the Nobudou Kit

Ursa is the boss that immediately follows the campaign's strangest encounter, and the one our boss list has been pointing you toward since Chapter 7. One fight, no rematch, Level 46, weak to Acid — and after several chapters of accumulating an acid toolkit, the game finally presents the target it was meant for. Here is where Ursa sits, what it pays out, and what our coverage genuinely knows about it.

Compiled from this site's own launch guides · Last reviewed September 11, 2026

Where you meet it

Our boss list gives Ursa a single appearance: Chapter 10 — the chapter titled, fittingly, Malefact — with the boss at Level 46. There is no rematch and no earlier encounter, so like Corvus and Erymanth this is a one-sitting fight.

Its position in the running order is the thing worth planning around. Our walkthrough closes its long-west-road stretch, Chapters 7 through 10, with Corvus at Level 38, Kunai & Kirin at Level 45, the Crimson Malefact wall in Chapter 9, and then Ursa at Level 46. Ursa is the last fight before the campaign turns toward the capital, and it arrives immediately after the encounter that strips half your kit away.

Koo is back

That sequencing deserves a paragraph of its own. Chapter 9's Crimson Malefact is the campaign's one Koo-less fight: our Koo guide records that the entire parry-to-FP-to-Bloom-Arts loop is unavailable for that encounter, and that Emma faces it alone at the top of Starfall Tower roughly eighteen hours in. Ursa is the fight immediately after.

So the practical note for Chapter 10 is a re-adjustment rather than a new skill. Whatever self-sufficient, Emma-only habits Chapter 9 forced on you — hoarding your own healing, treating every opening as something you create yourself — can be unlearned here. The command menu is available again, the Florescence Point economy works again, and the Koo guide's spending rule applies again: fire a Bloom Art as an enemy's Down Gauge approaches full, converting a stagger into a stun rather than a few extra hits.

The Acid weakness and its caveat

The boss list records Ursa as weak to Acid, and our review repeats it, grouping Ursa with Taurus as the roster's two Acid-weak bosses. Both the boss list and the walkthrough then give the same instruction, and they give it early: bring the Nobudou acid kit you took from Corvus in Chapter 7. The boss list goes further and says the game by this point assumes you are choosing elemental counters deliberately rather than stumbling into them.

The caveat is the same one that applies to every non-Fire, non-Lightning weakness on this roster. Our weapons page confirms exactly three enchantable elements in the shipped build — Fire, Lightning and Wet — and states that the full enemy-weakness chart was still being catalogued after release. Acid is not among them. So the documented acid delivery is the ability line: the Nushi Skill Acid Burst Nobudou, the art Nobudou: Burst and Blade Art: Nobudou from Corvus, plus the acid-type group art our Koo guide lists among the Bloom Art effects observed in play. Whether acid ammunition exists as a separate enchantment is not confirmed here.

What it unlocks

Ursa's reward column lists Asagao: Boa II and Finisher: Asagao — and note the roman numeral. The second rank arrives without this site recording where the first rank came from. Our pages do not name any boss that grants Asagao: Boa, so where the base art originates is not confirmed; it may come from a skill tree, a chapter event, or a source our coverage has not catalogued.

What is clear is the category. No Nushi Skill is attached to Ursa, which matches the pattern our Koo guide describes for the late game: the documented Nushi Skill order ends at Acid Burst Nobudou in Chapter 7, with the remaining seals contributing art upgrades and Finishers instead. Ursa, Erymanth and Kunai & Kirin all fit that shape. If you were hoping the last stretch of the campaign would keep handing you new abilities, it does not — it sharpens what you already have.

Loadout notes

  • Re-equip for Koo. If you rebuilt around Emma-only sustain for Chapter 9, undo it. Stones such as Florescent Recovery, which the Spirit Stones guide lists as making Bloom Arts restore 0.3% to 0.8% of Emma and Koo's health per second for five seconds, only do anything when the dog is actually with you.
  • Stones that pay for exploiting a weakness. Sharpshooter gives a ranged weakness-exploit a 20% to 30% chance to return 1 FP, and Entanglement Increase gives any weakness-exploit a 3% to 7% chance to restore both the Entanglement Gauge and FP — both from the same guide, and both live against a boss with a recorded weakness.
  • You should be near six slots. The Spirit Stones guide describes the cap rising from four early on to six by the end of the game; Chapter 10 is late enough that it is worth checking whether you have unused capacity sitting idle.
  • Boss retries are cheaper than they were at launch. Our patch notes record skippable cutscenes arriving in version 1.0.9 on August 24, which the page credits with making retry loops on story-adjacent bosses much faster, and 1.0.10 optimising boss-battle performance.

Completion data

Ursa's End stands at 24.8% of Steam owners on our trophy page's August 31 read and 26.0% on the achievement tracker's September 7 refresh of the same statistics. It is the highest of the four achievements in the late-game cluster on both reads, which is what you would expect from the earliest of them in story order.

Practically, the numbers say this fight stops almost nobody. The trophy page's reading is that the ladder flattens after Corvus and nearly everyone still playing reaches the credits; Ursa sits well inside that flat section, less than a point above the final boss on the August read.

What this page does not claim

We have no attack list, no phase description, no arena and no creature description for Ursa anywhere on this site. We also do not know where Asagao: Boa I comes from, or how acid is applied outside the Nobudou arts. Those gaps are stated rather than filled, which is the same standard our Crimson Malefact guide applies when it flags a disputed weakness instead of picking a side.

Ursa FAQ

What chapter is Ursa in?

Chapter 10, titled Malefact, as a single encounter with the boss listed at Level 46. There is no rematch.

Do I have Koo for this fight?

Yes. The one encounter without Koo is the Crimson Malefact in Chapter 9, immediately before this. Ursa is a normal two-character fight.

What should I bring?

Our boss list and walkthrough both say to bring the acid kit from Corvus. Ursa's recorded weakness is Acid, though the weapons page does not list Acid as an enchantable element.

Does Ursa grant a Nushi Skill?

No. The recorded rewards are Asagao: Boa II and Finisher: Asagao — art upgrades rather than a new Nushi Skill, which matches the late-game reward pattern.

Sources on this site

Every figure above is drawn from the following pages of this guide, each of which names the outside material it was checked against:

Last reviewed: September 11, 2026 · Game version checked: 1.0.11 · Every figure on this page is sourced from the pages listed above; where they disagree or fall silent, this page says so instead of choosing.