Really a good game, well done and with good music. i'm amazed. all turn-based RPGS should be like this!! this style is really comfortable. PLEASE CONTINUE DOING MORE!!
Against a group of 6 monsters, use an ranger with a good bow (Example Foe Piercer: good damage, dex, % to stun or kill) and cast "Hail of Arrows" // 2 hits per monster (2x6>12x9(% of lethality)= 118% chance to kill monsters [this means "at last 1 monster will die]).
Combine with Anoint (Cleric) or with Electrical Storm (Mage) as "Biopower" said {If the mage has a good staff (% to stun, kill or applies poison, is better}.
Massive Damage to all the monsters + % of Lethality ( good move) ;)