Yet another thread about Malack's alignment..

[Winter]

Neither conquest nor deceit are inherently evil. Brutal subjugation is, but if Malack doesn't personally participate in that and believes Tarquin's "greater good" justification, it is possible he could still squeak through as neutral.

Now you're kidding yourself.

Malack has been adventuring with Tarquin for decades and has been orchestrating Evil Empires that rule through oppression in changing setups for years.
I very much doubt it is even remotely possible he doesn't have his part in this (and it's even more impossible he does not know all this, as you claimed).

Belkar = Evil.
Thog = Evil.
Redcloak = Evil.
Malack = Evil.

All four are utterly evil and about all four we have to endure all the same debates over and over again.

To address what all those four have common: Just because you like a character it does not mean he's not evil.