I went to the island and when the page loaded, I found out that there were two monsters on each side of me. I don't know what bout I find myself saying that this quite unfair.

Because of the procedurally generated nature of the islands, this is actually pretty common. Unfortunately you just need to challenge the weaker one and hope you beat them...

Later on in the game, when you have pets with good genes and GPL your pets will be virtually indestructible, so just consider this beginner hazing.