Here are some of my ideas for traits . So I want to suggest the introduction of elemental traits that benefits specific elements and exclusive to those elemental.

• Superhero : self immunity to possession and team immune to own elements. Some monsters eligible for this trait are voltaik, firestorm, cyan nathura , lux aura , dusk aura and maybe tesaday

• Cloud control is a trait like status caster but this boosts damage from skills of specific elements and also introduce weather phenomenon on battle field

• Summer heat : boosts damage from fire and
  light skills by 60% . Also
  increase dot by burn ,ignite and
  sunburn by 10%

• Monsoon : boosts damage from water and
  thunder skills by 60%. Increase dot of drown , freeze and shock

• Springbloom : boosts damage by nature by 60 %
  *Moonlight : boosts damage by dark and light by 60% . Increase dot of nightmare, sunburn

Other trait ideas

• Lightspeed : doubles the speed of the monster at the star of the battle
• Purge : at the start of the battle kills one random enemy . Does not work against immune to sudden death
• Sacrifice : kills one random monster except itself and aquires the trait and stats of the sacrificed monster
• Zombie : immune to control. Can only be killed by sudden death moves . When a monster with this trait attack a monster , it also becomes a zombie
• Mastered : status effect have 40% less accuracy
• Angel : immune to dark attacks . Does double damage against dark , underworld and evil legion monsters
• Aerial : immune stun and eeth attacks . Also immune to quicksand
• Breserker : increase attack by 50 %
• Rouge : doubles the damage the monster . 10% chance of attacking allies
• Fortress : doubles the life of the monster at the start of the battle
• Rebirth: when the monster dies , it resurrects itself once with 50% life and stamina in a battle
• King of darkness : all allies becomes immjne to dark attacks, possession and torture . Self double damage against light and good legion monsters . Exclusive to Barbatos