Flanderization: He began as The Ditz, but moved on to Cloud Cuckoolander. More recently, he has surpassed this, and some fans are starting to suspect he is in fact clinically insane. (This may explain why Ethan made a Heroic Sacrifice to prevent a dystopian future from happening, and the entire strip is going to be rebooted.)
Red Oni, Blue Oni: He acts as The Red to Lucas's Blue, though ironically Ethan is dressed in Blue with Blue Eyes and his Winter-een-mas King Outfit has a Blue Cape. There is even a Cross Over Example in AdventureQuest Worlds with him acting as The Red Oni to The Hero's Blue Oni.
Too Dumb to Live: According to Zeke, if you run the data from Ethan's various misadventures, his life expectancy comes out negative. Negative forty.
Unexplained Recovery: He jumped off a second or third-story fire escape in his underwear because according to video game logic if he's lighter he'll be less injured. He lands on concrete and winds up with about two inches of bone sticking out of his arm. He goes to the hospital and is sent home the same day (in real life he'd probably have to stay for at least one night's observation) with "Paaaaaaaiiiiiiiiin killers!" and a cast. The next comic he's featured in there's no evidence he was ever injured despite having a break that would've taken months to heal (then again...) and would've at least left a nasty scar.
Feeling that he had taken the original cast as far as he could go with, Tim Buckley announced on his blog that the strip will now feature the Players (side characters once used for violent gags) as the main cast. They consist of Player 1 (Blue), Player 2 (Red), Player 3 (Yellow) and Player 4 (Green).
Took a Level in Kindness: Somewhat. They don't seem to try to brutally kill each other as often as they did when they were side characters, and get along quite amicably nowadays. Red is the most noticably changed, all of his past appearances had him trying to kill somebody.
And I Must Scream: Some of his arguments with Ted seem to imply that this trope is, at least partially, in effect. Particularly when it comes to killing Ethan off.