Fairytale Fights

In my opinion, the easiest way to do this is with a spare controller on the first chapter of the arena. It was pretty time consuming for me, but all you have to do is repeatedly kill the other player, tap a button on their controller to make them respawn and repeat. Total, you will need to kill them 500 times.

While working on this achievement, you can also unlock King Pushy (win only using push), King For a Day (win a match without dying), Unstoppable (win five matches in a row) as well as at least Weapons Are For Babies (250 kills without a weapon) or Master Slicer (250 kills with a sharp object).

You will want to use the second controller to give you a character to wail on for an hour (I signed in a Guest--not sure if that matters). Go to the inn and load up Arena Mode. Pick the 3rd chapter (the one on the clouds), with 5 point rounds and NO time limit. The "Unstoppable" achievement has problems unlocking if you don't actually kill the other player 5 times and simply let time run out, even if it says you won, so I wouldn't risk it here.

Press Start on both controllers to skip the intro (every time). Simply jump, straight up or toward the other player, and start moving the right stick left and right. Your character will perform a kick that sends the dummy player flying off the cloud. Press A on the dummy controller to respawn. Do it again 4 more times. You can finish an entire round in under a minute.

If you don't already have them, you will unlock "King For a Day" and "Unstoppable". If you feel like it, you can simply hit the dummy player 10 times while unarmed to work toward "Weapons Are For Babies" as well, though that will significantly slow you down. Do "King Pushy" while you're here, though.

EDIT: I used Red Riding Hood. Not sure if that makes a difference with the kicking move.

Very easy yet a somewhat timeconsuming achievement.

Absolutely the fastest way to do this is go to Arena Mode and load up the third chapter (Wishing on a cloud). Go for 5 points per round and no time limit. Plug in a second controller and you're ready to go. It doesn't matter what characters you choose.

Set up player 2 just on the edge of the cloud. Put your own player just behind it and press B (push). The second player will fall of the cloud and die immediately. He will respawn somewhere on the cloud (press A to gain time). Put player 2 on the edge of the cloud again (just in front where you left your own character). Press B and player 2 will fall of the cloud again. After five kills you've won 1 Arena chapter.

From here on rinse and repeat for another 99 times. It'll take about an hour to grind but then you'll have the achievement.