i've seen a video of Duped 5* X-23 (4/55) with the long timer taking on LOL Rulk. she one shotted him. also best option as you are going to regen the damage you take. i don't know how is she going to do Unduped. though mine who's Unduped at 3/45 does some beastly damage with her bleeds.
5* R4 X23 with full suicides and deep wounds masteries and attack sinergies... Assuming that it reaches extended enrage time, even unduped. Try a fight with rulk with a attack team sinergies (See recommended teams here), if reached extended enrage time, X23 could save a couple revives with the sustain that gain with regeneration.
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I think X23 could be better if you use suicides as well since you can regen. Bring a full attack team for the timer.