Adventurer of the Unknown Diana

Costume Guide – Adventurer of the Unknown Diana

Official Patch Notes



  • The highest potential supporter in the game right now in terms of pure damage potential, increasing element damage by 200% and crit rate by 30% at +5.
  • Crit rate buff is one of the most important buffs, as it allows you to focus your gears on crit damage.
  • Versatile for both physical and magical teams.
  • Reasonably low SP cost (2 SP at +3 onwards).
  • Long buff time (8 turns).
  • Exclusive gear has the 54% HP stat and 9% magic resist stat which means that she is reasonably tanky.
  • Dispatch field ability is one of the most useful field abilities, and has the chance to earn Dia.


  • Element damage is situational.
  • Aura means that she must stay alive for her support skill to take effect - if she dies, you lose your support power.
  • Aura range does not affect the whole field, which means that placement options are limited each turn (though she can move around).
  • You need multiple copies for her to be worth it. Diana at +0 is not very good, given that 3-star Arines (available free to all players) has comparable support abilities for less SP cost.

Diana for PVE

Diana is likely to become a staple for those looking to high score in Evil Castle or take on end-game content. No other supporter in the game can reach her level of damage potential. By way of comparison with other supporters:

Costume (at +5)Attack boostCrit rate boostSPOther
AOU Diana200%
(element only)
30%2Aura (limited range)
Homunculus Lathel130%
(ATK only)
0%1ATK buff drops 50%
after 2 turns
B-Rank Idol Helena75%
(M.ATK only)
50%2Moderate heal (4 turns)
Red Hat Rou0%50%3Gives Energy Guard
to whole team
Kind Student Samay50%
(ATK and M.ATK)
0%1Minor heal (2 turns)
(ATK only)

Although Diana has the limitation of only boosting elemental damage, this is not a huge limitation in end-game PVE (e.g. Evil Castle and Very Hard character packs), because most of the time you will already be using strong-element attackers to maximize damage.

Diana can be easily paired with another supporter to reach near 100% crit rate. For example, AOU Diana +5 and B-Rank Helena +5 together would give 80% crit rate, which could easily equate to 100% crit rate after taking into account gears and innate unit crit rate (most units have innate 10% crit rate). This makes AOU Diana a perfect choice for end game PVE story content, which requires very high damage to clear.

This also makes AOU Diana a perfect choice for Evil Castle high scoring, as high scores are calculated on the basis of the highest damage in one turn.

One drawback of Diana, however, is that she is not the best for PVE levels where you need to sacrifice units. For example, in the recent fiend hunt, you could use a supporter skill and then sacrifice that supporter the next turn, while still keeping their buffs. This strategy would not work with Diana, because you lose her buffs when she dies.

Diana in PVP

Diana is not very useful in PVP as elemental damage is highly situational. In addition, the overkill damage from Diana's skill is not really necessary in PVP (especially if you are already attacking with a strong element). Diana is therefore primarily a PVE unit.

Dispatch field skill

Diana is worth having at least one copy of for her field skill, Dispatch.

Like Olstein's skill, you can use Dispatch daily to earn free rewards. Diana's dispatch is arguably even better than Olstein's though, because you have a chance to earn Dia every day.

For this reason alone, it's worth getting at least 1 copy of Diana from the Chapter 10 pub.


At the moment, Diana at +5 is the best offensive supporter for PVE content. She is kind of like combining the power of Arines +5 and Homunculus Lathel +5 into a single unit (for on-element damage).

In terms of whether you should pull, the question is whether you need her. Getting her to +5 is a pretty big investment. It's always worth bearing in mind that powercreep is inevitable in all gacha games, so even though Diana is the best offensive supporter in the game right now, we are sure to get better and stronger supporters in the future.

Since Arines exists and is a decent "cheap substitute" for Diana, there are two reasons why you might need to pull for Diana right now. One is if you want to go for high-score ranking rewards in Evil Castle. The other is if you can't wait to clear end-game PVE content such as the Very Hard character packs, and need that extra bit of damage boost from Diana's skill. It's no coincidence that the devs have released Diana just after they released very hard PVE levels, to tempt you to pull for Diana.

If one or both of those reasons apply to you and you decide to pull for Diana, then be prepared to go all the way to at least +3 (and ideally +5) for her to be worth it. Otherwise, I would recommend you skip this one and keep using Arines.

A free copy of Diana is available from the Chapter 10 pub after clearing Chapter 10.