First beat the final boss. Then, go to the place where you fought Slival on Mt. Krakatroda. Defeat him again (He will have 3000 HP) and you will unlock the Schwarzen.
Beat the final boss and rescue all 100 slimes. Then, beat the final round of Tank Masters mode (against Hooly and the Shogun).
After saving Meggan, go to the northwestern house in the mid-part of town and talk to her.
|Knightro||Y, L, L, Y, R, R, Y, up, down, select|
|The Nemesis||Y, R, R, up, L, L, Y, down, down, down, Y, Select|