So. Melina Frost.
Profile: Well, aside from the fact that I'm pretty sure the Irish Mafia isn't really a thing (according to Wikipedia, there's an Irish Mob, but that's something different), there's the fact that Melina's whole personality in-game stems from a sexual assault that happened when she was a young teen. That, combined with the fact that her own wiki page admits that she's a copy of Mariavel Varella, pretty much sets the tone for Melina's story.
Pre-game: We get a memory thread in which Melina is either thirteen or fifteen (she's stated to be fifteen, and then in a later paragraph she's thirteen? It's a oneshot so we don't get any clarification) that covers the sexual assault mentioned in her profile in really gratuitous detail. I'm pretty sure we can all understand the problem with "assault victim turns nymphomaniac", so I won't go into detail here. After that, Melina appears in the beach party thread, where she beats up Eduardo Trinidad-Villa for no reason and then leaves.
V3 Proper: As much as I was complaining in chat, Melina wasn't really excruciating so much as mostly underwhelming with a few moments of shock value thrown in. Spelling and grammar errors are pretty rampant in her posts, and for the most part they're pretty short. Melina tries really hard to pull off the "master manipulator" archetype and this doesn't work because A) everyone she meets already knows her as a manipulative bully and B ) her only tactic ever is crocodile tears, which she usually ditches in about two posts anyway. There are some attempts later on to make Melina more sympathetic and vulnerable, but by then she's already done so much crazy shit that it's a lost cause. Then she goes inactive.
Death: Melina's death was handled by SOTF Help after she went inactive, and while it was a vast improvement in general writing quality, I'm not really pleased with the fact that she managed to kill two more characters, who weren't inactive themselves, in her death thread. It was a decent enough ending for Melina's character though.
Overall: I'd be more forgiving if Melina had more of a concept than "psycho bitch who will have sex with anyone", but as it is, she's just a failed attempt at a Mitsuko Souma-style villain. If you want an all-girl death squad, read the softball team from V5 instead.