While we are being first introduced to Kleve as an antagonist, I'm trying to make sense of his motivation for war.
First, he's explicitly told that there aren't enough Utroms left to operate military machinery by Ma'riell. On top of that, Honeycutt explains to Donatello that the majority of the Utroms surviving on Burnow
don't have military backgrounds. If they plunged back into war with the Triceratons like Kleve wants, there would be absolutely no surviving. It's why Krang was in such a rush to save as many Utroms as he could, get them into the bunker, and keep them in stasis while he made a new home for them. They're hanging by a thread; their only hope of survival is to lay low and repopulate. And yet Kleve is ignoring that, probably out of anger at their losses on Utrominon. As far as it feels to him, the war has only been over as long as he's been awake - rather than the three hundred years or so that Krang had to experience on his own.
Second, assassinating his preferred leader's sister would be a terrible idea unless he hoped he'd have a reaction for that. As I brought up to Bobby Curnow (who explained that Paul Allor didn't realize that Ma'riell and Ch'rell were siblings), it would be in his benefit to remove Ch'rell's last close relationship in order to initiate a second attempt at war with the Triceratons. Which they would lose very fast. But at least he'd get what he wanted out of Ch'rell besides ensuring his right to leadership.
I do have my own theory on what's going on, but it goes into conflict with the last point and by most of his behavior in TMNTU 22 in general.
And it comes from this little scene. In one of the most bad@$$ displays an Utrom has done since Professor Obligado. That's right off a reel from an 80's action flick, I tells ya.
He could be speaking in a broader sense, but it wouldn't be surprise me if at least part of the 'women and children' he was referring in part to his own family - to his own wife and children.
...You know, that makes it sound like he's what Hamato Yoshi would have become if he had somehow escaped Saki's murder of the boys. Somewhat at least.
I guess by unseating Ma'riell, he not only gets rid of the pacifist uniting with the species that drove her own people near to extinction, but also creates "if I'm going to lose everyone, someone else has to as well" philosophy - which works with Ch'rell because not only is he his preferred leader but also an ideal target.
He's a warhawk for sure, but even worse, he's a dumb@$$ warhawk.
Slap me in a blue dress and call me Alice, because I'm so far down the rabbit hole, I'm in Wonderland
