Technically Satan

In League, there are two Satans that I know of. These champions are also known as their alter egos: Teemo and Morgana. Teemo is known as Satan because he has so much poke early game, there's almost nothing that you can do to stop it. His Q does buttloads of damage and his E gives his auto attacks poison. Not to mention his ult which turns the map into a minefield of deadly mushrooms.

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Proof of Satan Teemo

We're here to talk about Morgana though. She's Satan for two reasons. Her tagline is, "Fallen Angel", which is also what Satan did, fell. Her Q, which is really dumb, like I can't express how dumb it is. At max level it snares for 3 seconds. That's a long time for an MMO. It snares long enough that you die before you can walk again. It literally cripples you.

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Morgana'a Dark Binding

 Her passive also gives you bonus spell-vamp so her W is actually a heal move. Her W puts down a circle of "Tormented Soil" that does damage over time withing that circle.

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Morgana's Tormented Soil

Her E is another reason to despise her. It blocks magic damage and effects from enemy champion's abilities. This is what makes her a good support. She can save the ADC from an engage with a quick press of a button. It's really useful for "peel", which is when you run the hell away.

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Morgana's Black Shield

Her ultimate allows her to deal a ton of burst damage. She can only activate it when there are champions nearby. She initiates it and if she keeps enemy champions in a certain radius, she deals more damage and stuns them for a little bit. 

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One time I was playing her as a support with a Sion ADC. Sion wasn't a meta pick so I was skeptical at the beginning. When we got in the game I leveled up my snare first and made my way to the bot lane. I snared their enemy Teemo, (Not very meta either) and Sion got first blood. That was very surprising. A little while later I snared their support, which was a Lux, and we got her very low. She was at about half health. Sion used his E to scream at her and slow her, she was at a third health after that. Sion then started his Q, which charges up the longer he holds it, he managed to get a full charge with the enemy Lux still in the range. I was sure that the Sion wasn't going to get the kill on Lux so I started walking away because we were really susceptible to a gank from their jungler. I saw the ax   D-D-D-Drop and Lux disappeared. I was very doubtful at the beginning but Sion pulled through and carried the game for us. Overall, Morgana is an awesome champion that is a lot of fun to play.