Should You Pull?
Maybe, leaning toward a Yes. Reisen Udongein Inaba (Eternal) is facing some rough competiton like her other A-Type Friends, this time being B3 Sagume Kishin, being one of the best Ultra Festival Friends out there, the all-around good of B3 Reisen Udongein Inaba (interesting coincidence) and Sanae Kochiya, and other A-Type Multiverse Friends, specifically A12 Byakuren Hijiri (though for less than a day at the time of writing...) and A6 Cirno. While the Moon EX Festival is also ongoing for Moon EX Battle Stage, Reisen has a good amount of Moon herself to be a viable last-second pick. What truly edges this rerun Festival over the others is Reisen's own viability, as well as the additional element to this Prayer.
Reisen herslef holds a lot of utility outside of Moon EX, having a very wide variety of elemental and anomaly breaks to make her a very handy team player, even without many team-wide buffs. Along with that, instead of being rerun with another A-Type Friend, Reisen has found a cool 5* Card, Overwhelming Firepower, to co-run with. Veteran players will know its use as one of the best Yin-based offensive cards, granting 3 levels of Yin ATK UP and a good Yin ATK stat stick. These two elements combined make this Prayer almost on par with the A6 Reimu Hakurei and Marisa Kirisame rerun.
Reisen (Eternal) will be available until April 25th, in which she will return to delivering her master's medicine and not be found until another rerun. Reisen can be exchanged for 150 Exchange Points, while one copy of Overwhelming Firepower can be exchanged for 50 Exchange Points. Alongside her Prayer will be an Ascending God Crystal Step-UP, allowing for 10-pulls to be done at 60 God Crystals initially and 100 more GC for each following step (60, 160, 260, 360, 460). Ascending Step-UPs are always a rather easy and cheap way to do one 10-pull on a Prayer while obtaining 10 bonus Fortune Dust.
+ Very high damage for both hard levels and farming
+ Solid Moon breaks mixed with other elements
+ Great team-wise speed buffs
+ Spell Card 1 covers all anomaly breaks
- Doesn’t scale nearly as well as other top tier units for longer fights
- Not many party-wide buffs; team supports her, not the other way around
[Numbers in brackets are buffs at Max Limit Break or stat sticks at Max Enhance]
- Yin ATK 2  levels UP (2T)
- Spell Card's Wood power 10% [15%] UP (1T)
- DMG from Moon element 15% DOWN (3T)
- HP +150 [+450]
- Yin ATK +30 [+90]
Reisen Udongein Inaba (Eternal)
Reisen Udongein Inaba is not an earth rabbit or youkai like Tewi Inaba or the rest of her peers. Instead, came from the Lunar Capital as a moon rabbit, formerly serving as the pet of the lunar emisarries and Lunarian princesses, the Watatsuki sisters. Fed up with the rigerous training while on the moon, Reisen finally snapped after the lunar war (around when humans first landed on Earth) and escaped to the Earth. Once there, she found herself in Gensokyo, specifically Eientei, home to two other Lunarian exiles: Kaguya Houraisan and Eirin Yagokoro.
Promising not to snitch on them (as Eirin was not afraid to kill to protect her princess), Reisen found a new home with the ex-Lunarians and learned under Eirin, referring to the doctor as her master. This would lead to her getting involved in the Eternal Night Incident during the events of Touhou 8: Imperishible Night (IN), as she defended Eirin and Eientei from the human and youaki invaders who found out about the fake moon. After this incident was resolved, Eientei opened up to the rest of Gensokyo as time resumed. Reisen would work with Eirin to provide medical services to humans and youkai alike, but Reisen would usually make the deliveries to the Human Village in her master's stead...
As this version of Reisen is from a universe in which the Eternal Night Incident was not resolved yet, her basic shots and spells are seen as "outdated." Of course, as with all other A-Type Multiverse Friends, that means very little in terms of viability. As a Speed Type Friend with some rather high Slicing scaling, her second spell, Lunar Eyes: Moon Rabbit's Remote Mesmerism (Tele-Mesmerism), raises the entire party's Agility by 3 levels (3T), allowing both her and other Slicing-based Friends to cause even more damage. Additionally, it inflicts 2 Blind anomalies to the target, which can later be broken by her Last Word, Stare of the Hazy Phantom Moon Remix (Lunatic Red Eyes Remix), when at 3P. Not only does this Last Word heavily raise her Yin ATK by 4 levels (1T), but it applies 2 Paralyze anomalies on herself. Thanks to her character ability, Capable of manipulating madness, each layer of Paralyze or Blind raises her own Agility and Accuracy by 1 level, serving as more damage and even Accuracy support. Like other Friends who get buffs off of self-anomalies, Reisen does not get affected by the drawbacks of being stunned from Paralyze or less Accuracy from Blind (that would be pretty counter-intuitive anyway...)
While those two spells may synergize well with themselves, Reisen's first spell, Spread Sign: Moon of Truth (Invisible Full Moon), takes it to a whole different level. Not only can this spell break Blind anomalies at 2P, it can break Burn, Freeze, Poison, and Paralyze anomalies as well, giving Reisen anomaly break coverage of all 5 anomalies! This allows Reisen to synergize with many other anomaly inflicters as well. Her elemental break coverage was already impressive, with each spell having dual-elements, with Spread Sign: Moon of Truth (Invisible Full Moon) having Moon and Water, Lunar Eyes: Moon Rabbit's Remote Mesmerism (Tele-Mesmerism) having Moon and Metal, and Stare of the Hazy Phantom Moon Remix (Lunatic Red Eyes Remix) having Moon and Sun. It is unfortunate that her normal spells are Solo-target, making both the Blind anomaly inflictions and anomaly breaks limited to a single target, but Reisen still gains great utility from these tools.
As for her skills, thie eternal moon rabbit keeps on buffing herself. Her first 2 skills, Physical Waves and Emotional Waves, share a very similar approach. 2 layers of Paralyze with 2 levels of Yin ATK UP (2T) for the former and 2 layers of Blind with 3 levels of Yin ATK UP (2T) with the latter. These are pretty self-explanatory with how these 4 anomaly layers combined already give 4 levels of Agility and Accuracy UP as long as they are on Reisen. Just make sure that these anomalies aren't broken by the opponent! Lastly, her third skill, Intellectual Waves, is 2 more levels of Agility UP for the team with an 80% chance for an extra level (3T) while also giving herself 1.0 Spirit Power to use on whatever attack she'd like.
All in all, Reisen (Eternal) is just an incredible Friend who is not afraid to show off their selection of moon rabbit powers. She might not be enough to make it to the top of the tier list and provides little for the team buff-wise outside of Agility, but she still have very high utility while dishing out good damage. Give her a pat on the head for a good job. I heard she likes that.
If you would like to learn more about A8 Reisen's original world, check out the lore article below!