Much like my last one I'll be going over the Maskeraith base and ults...
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When you start out the Maskeraith is immediately useful... the Quills make killing key targets like turrets fast and the poison gives an offense and defense perk since it cuts enemy damage and defense...
The Cloak is useful immediately too since it gives a knight breathing room to escape and re-position or more safely use HP capsules...
The Haze too is useful though by the time you gain access it only proves really useful when dealing with masses of enemies, otherwise the quills are better
The only buff I'd give is giving it the ability to deal poison to enemies that are immune to poison.... perhaps make a unique status called "Maskeraith poison" functionally identical to the existing poison but is not affected by status resist and immunity
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Both Quill ultimates seem to be quite useful on first glance but the Virulent suffers from terribly short range while Vengeful is good but not the best it could be...
Give the Virulent quill explosion something along the lines of a 2 Star Blast bomb radius of effect to help
Give the Vengeful quills targeting to try and affect the nearest enemies... not the ones across the room
Both Cloak ultimates also seem useful... but even after the flash charge nerf the Deadly Cloak is still better than the Vengeful one
To improve the Vengeful cloak you could improve the Stun Blast radius size and perhaps even give enemies afflicted a defense drop making it a good support and revenge options
Again like before both seem like powerful options... however Haunted haze has the caveat that the enemies have to die by the haze to activate the effect... on top of that the ability is currently bugged and doesn't scale to depth...
Buff Haunted Haze's ability to go off when any enemy in it's influence dies in any ways (just like Violent heart attack) and fix the issue with it's damage scaling.... I'm figuring that even dealing a third of the damage with the ghost that the Haze can deal with itself can turn into a useful KO chaining skill
Chaotic haze is just useful... the only buff I'd give is that it doesn't attempt to apply a status to an enemy that is immune
A lot of fixing rather improving, you also explained why some options are viable at his core, but perhaps not in practise, as of now.
I'm not sure about giving: "...Virulent quill explosion something along the lines of a 2 Star Blast bomb radius of effect to help", a little bit better than now, would be really useful and helpful
P.D.: looking for the review on the flying Lizard