Should You Pull? Festival: Subterranean Subconscious

Maybe. Koishi is certainly a strong Friend with colossal Yin attack, but at the end of the day she doesn't provide much team support and only really does a ton of damage. Which is not a bad thing, of course; but if you're a high level player with a ton of attackers, Koishi will probably not add a completely new angle to your teambuilding possibilities.

Koishi is very fast, has a lot of Fire and Water breaks, and does good AoE damage. If none of these things are filling out a needed slot in your Friend box (or you just really like Koishi), you might want to consider putting your energy towards other ongoing Prayers like Remilia (L80) or Patchouli (A6). Just like all Festival Friends, Koishi can be exchanged for 150 Exchange Points in this Prayer.

This prayer will run with a descending God Crystal Step-UP. Just to refresh on the mechanics of this Step-UP, It costs 600 God Crystals for the first 10-pull, just like a normal God Crystal pull. Then, the rate drops to 400 God Crystals on the third step, and 200 God Crystals on the fifth step. As for the second and fourth steps, they are completely free of charge! You still obtain Fortune Dust from the free steps, which practically gives you 20 Fortune Dust for only 600 God Crystals!

+0P AoE Fire on Focus Shot
+Great damage all around, and almost entirely AoE
+Is very fast and will almost always go first
+Almost completely Yin focused with extremely high Yin ATK
+Inflicts lots of Freeze and Yin DEF Down, and has Thawing on Focus Shot 1P

-Gives out very little team support
-Really wants Yin attack and Speed support to maximize damage

Koishi Komeiji is one of the Komeiji sisters, along with her older sister, Satori Komeiji. They live together in the Former Hell deep under Gensokyo, in the Palace of the Earth Spirits, along with their large selection of pets, including Rin Kaenbyou and Utsuho (Okuu) Reiuji. In the events of Touhou 11, Subterranean Animism, Koishi follows around the incident resolvers for most of the time, but goes entirely unnoticed due to her ability to "manipulate the unconscious mind", which can involve messing with people's senses' ability to percieve her, among many other effects. Only when the incident resolvers make their way up to Moriya Shrine does Koishi become noticed, in which she actively provokes a fight (and then promptly loses). However, she is no pushover, being an S+ Tier Friend.

Koishi Komeiji (Subterranean) is a high level Yin attacker with above average modern-day Festival Friend level of Element density, which is spread equally across Fire and Water. On top of that, her Spell Cards are mostly frontloaded (3-1-1), so her element breaks and damage are low cost and fast to get out as far as Spirit P goes. This also makes her 1 turn damage quite high, but her potential damage ceiling can only be very effectively hit with lots of Yin ATK and Speed support.

As for high level content, Koishi will definitely shine on Yin focused teams and do a whole lot of damage so long as she gets those buffs from her teammates, as lots of her Spell Cards have Sure-Hit bullet lines, and the base accuracy for those without Sure-Hit is quite good too. And to add to her regular element breaks, Koishi can also apply 2 layers of Freeze with Suppression: Super-Ego, and then also has Thawing on her Focus Shot at 1P for just a little more breaking capability. She also has Incineration on her Spread Shot 1P, although she doesn't inflict any Burn.

Koishi's Skills and Spell Cards aren't anything unusual coming from a Yin attacker, but they certainly get the job done; with her absolutely massive 1880 Yin ATK, and mostly Yin Shots and Spells, she can take full advantage of the Yin buffs she provides herself, the Yin DEF down she inflicts AoE with both Suppression: Super-Ego and Ancestors' Cemetery Garden, and do excellent damage with her Spell Cards and Last Word. And being a Speed type Friend, she gets a good bit of Slicing scaling on her attacks too, making Speed buffs effectively buff her damage as well as Yin ATK buffs.Just because she wants to be in familiar company and can't just be a standalone do-everything-solo Friend is far from meaning she's "bad"; it's really not a problem at all considering high level content needs full teams anyhow, so you might as well build them correctly.

Overall, Koishi is an excellent addition to any Yin oriented team, but it's possible that if you're a long time player, she might show some redundancy/overlap with other Yin attackers and therefore not be a top priority Prayer, especially considering the other Prayers still going on right now. But whatever you choose, good luck Praying!