Okai! :D I will be making headcannon's for all of the paths. Starting with Elboy! If you like these, tell me which character you want next. Did this on my phone, sorry if bad grammar and the like. Bye! :3
Elsword as a Rune Slayer shows a much more mature, but cocky side of himself. Unlike Lord Knight, he sees the brighter sides of things. Being much more outgoing than the other paths. Confident of his own skills, he always know he'll do his best protecting his comrades. Even though he didn't follow the path of his sister, he decided to let go of his sister a little bit and forge his own path. In his mind, this was the only way he could grow up more. He chose the path of fire in reflection of his firey personality, though it doesn't mean he won't learn the other rune elements. Rune Slayer is actually quite flirty, though not intentionally doing it at times. Complementing the person, showing the good aspects of themselves, Elsword is quite the positive reinforcement when things are down.
Lord Knight's personality is much more serious. Growing from a hot-head to a mature young man. Though, the hot headedness is still there,I t isn't as obvious. His confidence isn't as strong as Rune Slayer's. Questioning his own skills and constantly comparing himself to his sister. Reaching Lord Knight made him experience the taste of a leader. He feels that receiving the title made him more responsible in his position in Velder's Knights. This isn't the same Elsword anymore. Taking a darker side of himself, Elsword quickly learns the other aspects of being a knight than just kicking ass and swinging his sword.
A mix of both Lord Knight and Rune Slayer's personalities. He hold's his swordsman composure and ideals. He's quite mature and serious now, though cocky and confident, following his time as a Sheath Knight. He has a slight anger issue and will snap randomly, this is because of the Darkness he is trying to control. It represents the Dark side of Elsword. Even though it might seem that he's cursed with this, he plans to conquer his darkness. He no longer sees himself as a knight, just a swordsman now.