what is the easiest way to kill the king ludroth and the third monster..

use a lance

i say use a great sowrd. it worked for me on Barrith, gabul, and rathian, and first lagacris quest

Hello,

First of all, it;s Royal Ludroth and you can usually kill him with a Buster Sword , swipe at his tail first and when you've severed it head to his mane (spongey thingey) and when that's broken hit at his head to shatter his crest, by then he will limp and you can easily kill him if you head to Area 8, I got him on my second attempt!

Second, I think it's Barroth you mean- the big muddy thing? Yes, that's Barroth and he's what I call tough- use a Spiral Lance with mixed armour (rheneplos, Jaggi and Ludroth)to beat him.

I hope this helped

In the Arena, I would use anything you can to cut off both of the monster's tails, eliminating those makes a world of a difference. After that just play it safe, I know it takes a while but it will work eventually.