Myriad Colors of Phantom World is the most recent in-house Light Novel adaptation from KyoAni. Unlike the ones before they didn't even award it their own grand prize (after which they publish submitted works). For whatever is written in the original work not much seemed to have made it on screen besides the core concept of the phantoms (I have however little proof for this except the back blurbs google translations). The episodes are all episodic and varying greatly in quality, most of them are however bland setups for fan service and action scenes. Don't get me wrong, they can be creative... it's just that the whole cast and the battles they're put in are not engaging at all.
The characters have the depth of whatever waifu generator that is cool right now. Needles to say they don't need much of a personality. This also fits in with whatever (little) logic this world carries; each and everyone of them feels redundant as it's mostly a gamble as to whose power is able to defeat what phantom.
I have the feeling this wasn't anyone's passion project and the intended audience is probably quite young given the lengthy exposition intros every episode (or maybe that is related to them opening up an English website).