Killing Machines. Not uber killing machines or anything like that, just killing machines. They are one of the strongest attackers in the game, and you can get them VERY early. In the tower you use as your base of operations, go to the top floors and get some of the hunter killers. Merge two of them, you get a killing machine lite. Merge two killing machine lites, you get a killing machine. They're generally what I use for the bulk of my monsters post game, or slime knights. Killing machines have Act x2, which means they can do one skill you command them to, and one command from the AI. They also have Woosh Meister at higher tiers, so you gain more damage with Woosh attacks. Their default skill set is a bunch of elemental slashes (Including woosh), multislash, and multifist, so is a very very strong attack skill set. Their resists are fairly decent too at base levels. Act x2 lowers stats somewhat, but it basically doubles your damage, so in general, it's worth it. Or if you have them, you can use a healing move, THEN attack. Act 1~2, 2~3, or 1~3 is too random for my tastes for the stat cost. Besides that, you may want a metal king w/Material+ skill. This is one of the skillsets with Scapegoat, which lets you take all incoming damage for the team. While the MSK has almost no HP, they have great DEF stat, and resist almost all elements. Later you can get darkonium slime, who can ABSORB elemental attacks with ease. Get that + perfect crit guard, and you have someone who can tank almost anything; as long as the boss doesnt use a skill to counter scapegoat, such as disruptive wave in the middle of attacks. Even the bosses who do, however, this setup greatly reduces damage.