Battle Mage Secrets: Possibilus being Wise, grabbing the Opportunity

This is a Stampede ruleset game so The Trample ability can trigger multiple times per attack if the trampled Monster is killed.
Higher HP and speed are the key in this ruleset. Dispel helps to remove Trample.

This is an Unprotected ruleset game so Monsters do not have any armor and do not get armor from Abilities or Summoner Buffs.
Protect, Piercing, Repair, Rust are useless. Focus on a tank with high HP and Heal.

This is an Equal Opportunity ruleset game so All Monsters have the Opportunity ability.
Speed and HP is the trick here: higher speed will let you target enemy's low HP monster first, opening the way for your slower monsters to deal damage to higher HP enemy monsters. Keep lower HP monsters in front. Monsters who have two attack types should always be preferred.

Pos 1 Monster: Baakjira

Abilities:
Void - Reduced damage from Magic attacks
Attack damage gets halved (rounded up), except attack 1 which deals 0 damage
Slow - Reduces the Speed of all enemy Monsters
Strengthen - All friendly Monsters have increased Health
Heal - Restores a portion of the Monster's health each round
Restores 1/3 of the max health, rounded down.

Pos 3 Monster: Venari Marksrat

Abilities:
Martyr - When this Monster dies, adjacent Monsters get +1 to all stats
Snare - When attacking enemies with Flying, removes the Flying ability and cannot miss.

Pos 5 Monster: River Hellondale

Abilities:
Resurrect - When a friendly Monster dies it is brought back to life with 1 Health. This ability can only trigger once per battle
Inspire - Gives all friendly Monsters +1 Melee attack.
Dispel - When this monster hit an enemy, it clears all positive status effects on that enemy