(Only roughly 1 day to the new What Makes the Sky Blue event. I can't wait to know how the story is going to end!)
Dark Zeta is the best Zeta we currently have (until Fire gets an FLB at least) and a relatively good attacker in dark that packs:
1) First skill is a nuke that gives characters a 20% light incoming damage reduced
2) second skill inflicting burned and 15% dark def down (good for capping).
3) Third skill giving 100% TA for 3 turns out of 8 (cost 30% charge bar).
4) Guaranteed permanent echo on both normal attacks (20%) and charge attacks (25%) as long as you can land a burned which shouldn't be too hard considering she has it in her kit.
5) 10% dark atk up for 5.5 turns whenever she charge attack.
Her kit is, while a bit outdated, quite good for an attacker. I don't see much issues with her as a character aside from maybe the animation speed of her second skill (which can't be skipped because you need burned to get maximum damage from her).
Of course, Dark is full of good attackers which means she's only really a choice if you lack other choices that can make more damage than her or you need someone to cap def down when using an MC class that can't do alone (like Warlock).
