In the anime, Blaine is the only gym leader who tries to win his fights by actually killing his opponent's Pokemon.

He chooses to have his gym inside an active volcano. In the first battle, Ash had to forfeit because Magmar's Fire Blast almost knocked Pikachu into the lava. If Pikachu wasn't able to grab the ledge in time he'd be dead.

In the second fight, Magmar tosses Charizard into the lava. This shit is a deliberate tactic of Blaine's and he's probably had dozens of Pokemon tossed into the volcano over the years.

This guy is an asshole who needlessly decides Pokemon battles should be lethal. He could have built his gym in a field. He could have installed a safety rail around the platform, but no. Twice he uses the molten lava in an attempt to kill Ash's Pokemon. That is no coincidence and it would be crazy to think he hasn't killed Pokemon many times before.