One or two people fits to this template perfectly. Weak, soft, approachable in the beginning but, becomes silently more dominant and sucking your energy for their survival. If you cannot regenerate fast enough, they throw you to the side to find their new victim. Sad, damaging.
> These issues are probably intransigent...
My guess is TIV is not intransigent if you can attack it from right angle. The profile looks like grounded in good person turned bad for real or so, this looks like a winning strategy. Both foundations can be disassembled. First one needs someone who can cut through to anger to reach to the core of the personality. Second one needs an encounter with a bite-resistant person so, they have to think their strategy.
I'm overly generalizing here, but hope I could communicate the idea behind my rationale.