Otillie

Variety of Debuffs

Many people don't realize just how many debuffs Otillie can utilize. Her S1 causes Unhealable, and her S3 debilitates her target with CR reduction, Silence, and Unbuffable all in one fell swoop. Furthermore, her S3's cooldown is very low (only 3 turns after Skill Enhancement) and she can even Soulburn it to reduce the cooldown by 2 turns, which allows her to use it frequently.

Protection from AOE Damage

Otillie has a rather unique passive in her S2, Area Defense, which reduces the damage your party takes from AOE attacks. This is most obviously useful for Golem, as all of Golem's attacks are AOE, but it can be useful in other places too. Bosses often have AOE attacks, and the damage reduction may even help you survive enemy cleave teams in PvP.

Easy to Use

As a 3★ hero, Otillie is easy to bring up to speed, since she uses Stigma instead of Molagora to enhance her skills. Even more importantly, however, she's incredibly lenient in regards to gear. Since she focuses almost entirely on debuffs and her S2 passive, as long as you can get some Spd and Effectiveness on her, she'll be able to do her job.

Very Niche

While it's possible for Otillie to pull her weight in some circumstances outside of Golem, Golem is the only fight where she reliably shines. Her blend of lockdown ailments and AOE protection is very unique, but it doesn't have much application outside of her comfort zone. A strong Knight equipped with Aurius is usually going to be better at damage mitigation, and many other characters are better at locking down enemy targets.

Poor Stats

Otillie is both squishy and not very strong, which is one of the reasons she has trouble performing outside of the Golem fight. Her worth is based entirely on her debuffs and her passive, and those features are not always worth the sacrifice in damage output.