I bought this Sana concealer, not only because the packaging was cute, but also because it was well priced.
Who could resist this packaging?! (*´艸`*)
When I first swatched it on my hand, I was surprised as how YELLOW it was! Luckily it blends well enough. For those of you unaware, yellow helps to cancel dark under eye circles because they're on opposite sides of the colour wheel.
I found this concealer to have more of a brightening effect, rather than a masking, or concealing effect. This can either make or break this product depending on what you're going for. I think using this, plus a teeny bit of bb cream or foundation could would be ok to cover up any minor under eye circles or discolouration. For this reason I think this is mostly suitable for daily use.
If you're going for a complete concealing effect though, you're either going to have to really layer on this product (which is never good), or look elsewhere. For this reason, I would have to say cosplayers should look elsewhere for an under eye concealer.