Random portal

Monsters :

 * Squirrel + 1 HXP --> easy
 * Slime + 2 HXP --> easy, has high eva
 * Cellop + 3 HXP --> a bit harder high eva and HP, some damage
 * Minotaur + 5 HXP --> a bit easier than cellop, some HP and def.
 * Mini golem +7 HXP --> a bit harder because of high def and HP
 * Succubus + ? HXP --> too hard

Material bonus

 * Cash
 * Magic powder
 * Artifacts

Overall strategy
Vampire pot + agi/str + cdef + ceva + lowcrit works well except for succubus.