It's unfortunate for something like this to happen to the game's biggest project, but the Eihwaz series falls firmly under Fridge Logic with the conclusion of the second video set. At the end, Lilyrain EVE goes back in time and oneshots the Ark of Wrath that was about to possess the progenitor of her weapon. Eve and her friend Jace thank her, have a visit at the Cosmic Ark and all is right with the world, isn't it? Well... not really; here's where the Fridge Logic sets in. When the Ark of Wrath possessed Eve pre-Time Travel shenanigans, it resulted in her decimating her entire village; monsters, villagers, friends, everything. It's implied that she left her namesake cannon (or at least one of the two) in the ruins of that village before committing suicide... where that cannon was then excavated by the Cosmic Heroes, i.e. Lilyrain. At the end of the first Eihwaz presentation, she awakens Eve's dormant spirit from within the cannon and asks for her help, transforming her into Lilyrain EVE. But then she went back in time and prevented the whole disaster at Eve's village from happening... shouldn't this mean that Eve never abandoned her weapons, which means there were none for Lily to find, allowing her and the countless other Heroes she was protecting at the time to be ripped to shreds by Kisrill? And yet everything seems to be all sunshine and roses after the end of the second series. No Timey-Wimey Ball, No Hitler's Time Travel Exemption Act example, nothing. It's incredibly jarring and disappointing to not see this addressed, and unless CyberStep plans on making a third Eihwaz series to cover it, we're left to assume that They Just Didn't Care.
Actually, at worst it's a Timey-Wimey Ball with no real description, but if you think of it like this it makes sense: The Eve and Jace that were saved and pulled from the past have now created a new timeline in their dimension in which the town and their friends were saved, but in which Lily Rain would not receive Eve's weapon, and they were slaughtered by Kisrill. This is less Fridge Logic and much more Fridge Horror when you consider how the time travel presumably works. UNLESS the Word of God that the Cosmic Ark is actually connected to multiple dimensions rather than having one strict timeline is true, then presumably Lily Rain could receive that Eve's weapon from any timeline in which Eve's town and friends were not saved.
The Cosmic Ark being connected to dozens of different dimensions is sorta the whole underlying thing that makes the game's flimsy plot work, so we'd have to presume it's true. Within the first few moments of the game it's made clear that every Cosmic Hero on the Ark is from a different dimension, barring those who came along together like Resha/Eris, Elisalotte/Melfi, etc. The better question is why the Eve that was saved still looks like she's possessed in battlemode, unless you just take it as CyberStep lazing out.