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Chloe is probably the most specialized unit we've ever gotten, even moreso than Sorono, who has her ranged aoe to save her a bit from her lack of consistent dps. You need like 8/10 levels of Chloe's skill so she has more uptime than downtime, kind of nuts. Still she will be capable of saving your ass on certain extremely difficult event maps, I just don't think she'll be a constant on any teams, unless you really love her enough to use her over a more reliable duelist (I might

). I mean her stats are quite absurd when she's active:
HP: 1860 (Kind of average for her cost)
Attack: 836 (One of the best for her type)
Defense: 498 (Bonkers for a duelist type)
Magic resist: 20 (Highest out right now that isn't awakened or Sophie I think)
3 block, attacks two units at a time. All that without Prince buff. Her attack speed seems pretty great and she's even as capable at tanking as a HA.
Most interestingly, they'll be awakenable soon. We can only guess what Fallen Angel awaken abilities and passives will be. It also seems like more may be released in the future. So betting on her isn't the worst thing you could do, they have hidden potential we'll have to wait to find out about until their awaken abilities are announced. If you notice on the wiki as well, there's a huge boost in stats once they're CC'd (Sophie goes from 501-563 attack un CC'd to 565-716 attack when CC'd as an example), so they could easily become even more insane stat wise upon awakening.
I've changed my mind about her now that the wiki has posted her CC'd stats. I'm still farming her at 6/10 skill and -4/-5 cost reduction. She really needs high skill levels.
EDIT: FUCK YEAH, max cost reduction

I'm about to CC her too.