Kurokage tl;dr

• Constant chip damage. Some of it will gray out the HP bar. Only a portion (1/6 INS, 1/9 TOR, 1/11 LUN) of the gray bar heal will apply.
• If that gray area fills over half the bar, an eye will show up above your student and she'll get confused, making her shoot her closest ally. Cure by fully getting rid of the grayed out portion.
• Boss has 3 phases (P1 until 75%, P2 until 10%). P2 is more dangerous than P1 and P3 but has an opportunity for massive burst damage on groggy.
• Boss is actually 7 target balls, so use AoE damage. During groggy in P2, you have guaranteed crits and 4 more target balls to smack around, which will result in a massive amount of damage. Groggy gauge can only be filled by purple damage.
• Boss has a lot of DEF, so bring AoE DEF down like Kikyou, Kasumi, BAsuna, or Aomori.
• Boss periodically spawns exploding foxes that you can eliminate, might need a tank for them if you can't.