There is a hint, to the effect of "the same password as before." I had to dig a little bit, "before" turns out to have been "ekokijo".
Seems to be a modified version of Horuakuti's mating press Kuromaru with a partially-compatible* Eko. There are a few funky modifications, but the main additions seem to be a sort of puppet hand helper (D, D, x/D, D, y, costs 1 power bar. Move the hand with UDLR, makes light attacks automatically. Press a for heavy attack or b to send out puppet strings) and a pseudo-anti-air component in Kuromaru's crouch. It won't work if the opponent jumps or hops at you, but it does work if they've been knocked up/back or are held by puppet strings.
*compatible with the new features, but not the existing mating press. Which is weird, because Horuakuti made a compatible Eko at one point.