The problem with Deathmole is that they don't have a front (wo)man; Marten and Hanners are moderate-to-extreme introverts, and Amir is pretty laid-back. The closest they had was (what's-her-name), the chick who couldn't play worth a damn and was punk-proud of it. That went out as a success strategy in the late 80's. Say what you will about lead-singer "diva"-ness, some degree of that sort of Type-A drive is necessary. Even if one only plays the role onstage, someone HAS to play it!
Deathmole doesn't have a lyricist, none of them have inclination for songwriting. They're just noodling around on their instruments. Sven could write for them, but he'd have to be sitting in with them, collaborating, participating in whatever their artistic process actually is. Most real bands write their own. Pro songwriters can dash off tunes for Lady Gaga or Rihanna without face-time because they are well-known stylistic quantities. And Deathmole possibly hasn't even figured out what its style really is. Paying Sven what he's worth (even when he just squats out commercially-acceptable stuff like clockwork) will be impossible on an indie startup budget.
Some bands do amazingly well as three-piece (less than that just isn't sufficient, White Stripes notwithstanding). Deathmole is still missing elements. They
need a poetry/lyric writing lead guitarist and/or singer,
which with some solid (but perhaps not spectacular) musical chops. They haven't put their finger on that lack, beyond "we ought to replace what's-her-name one of these days". They haven't found anyone in their current circle of acquaintances, but don't appear to have been looking all that hard. If you can't find a friend who fits the bill, hit the classifieds and gamble with a stranger. Or a series of strangers until you find one that does fit. If you prefer the personal touch, check the corkboard at the local instrument shop, or hit local shows and schmooze the scene.
Marten will probably be happier shifting role to rhythm guitarist (with maybe an occasional solo to assuage his music sensitivities). Amir plays bass I presume? I don't remember and it's a god-awful lot of comics to review to find.
They also might be aiming themselves at the wrong style of music, starting with the band's name. How much metal or metal influence are they trying to pack into their sound?
They might be trying to sound like
Divyded when being something like
The Everyday Motive would suit their artistic and personal sensibilities better. Yes, I'm using regional bands I like for examples, don't hate on that.
But again, this goes back to them not just picking a target and going for it, but picking a suitable target!