Just did Mark Of A Hero for the first time, 15min left, not bad!
My tips:
Always have your health at max when fighting Lagi, his shock attack is very unpredictable.
Try to make Los and Brachy hit each other and focus your attacks on Los (easier to kill, or capture).
Don't fight Brachy if he is in rage mode, he WILL bitch slap you and finish with a combo, slime prevents you from blocking. He killed me two times because of this, one of the few monsters that really chase you down, there's no escaping, he runs really fast.
And of course, make good use of traps and flashes!
Tomorrow is Alatreon time!