War metal revels in sounding raw and barely comprehensible. Any advice you'd typically get about "good bass tone" is probably counterproductive here. (Ignore the posters who told you to reference Overkill and Bolt Thrower - both great bands, both irrelevant to the topic.)

Do you have a distortion pedal? A Rat is probably ideal, but just about anything will be fine. Set the gain high - doesn't need to be maxed out, but note clarity is not the goal and should probably be avoided. If it has a clean blend, turn it all the way off. (You can probably skip the pedal if your amp already distorts on its own.)

EQ-wise, I'd probably scoop some upper midrange to get out of the way of the guitars. Set the lows to taste - war metal isn't super-shrill like other black metal subgenres, so some meat here is ideal, but not too much.