Essentially you can play your muter in one of three ways in PK.
1) Duo + Meta Slow + Teleport/Word will keep you alive in most bad situations when you get hurt, so play super cautious and explore to your hearts content. You have bash protection and a nearly undetectable form of hide.
2) MELEE MUTER. You can slow your opponents and maledict them. You can haste and buff yourself. Gear for damage, get a noremove staff, and watch as you hit 3 DEVA's in melee as a mage. Note, in this form you're somewhat of a glass cannon, and if you lose your staff you are completely SOL.
3) Proper Way...a mix of the two above. Cautious, but prepared for War. Master your spells like disrupt flesh (causes bleeding), disrupt bone (causes some crazy mals) and disrupt organ (ditto). Fighting someone you can't out-damage or out-fight? Haste/Quicken them, give them gill growth and make them bleed...then kill them when they run out of mana/moves. If you run out of moves when accelerated, you pass out. Remember that for yourself AND for foes.
You can control the battle due to your hiding ability.