魔法使い means “wizard” or “magician,” making it a memorable choice that connects directly to the song’s title, WIZARD. In the lyrics, the speaker calls himself a 魔法使い because he uses seductive words and deception like spells, creating a darker, more playful meaning than a typical fantasy wizard.
This is a pick-up artist's victory lap, sung by a guy who is proud of being a heartbreaker. He calls himself a magician, "俺は魔法使い" [I'm a wizard], and the spell he casts is seduction. He smiles, strokes her hair, kisses her, and the whole time he's thinking "『バカな奴 その気になって』" [what a fool, getting her hopes up].
The fun part is the wordplay. He opens with a kanji lesson: look at the character 恋 (romantic love) and "ほら'下'に'心'があるだろ?" [see, there's 心, heart, at the bottom]. The joke is that 下心 means a hidden, usually sexual, motive. Later he does it with the alphabet: right after 'H' comes 'I'. In Japanese slang エッチ ("H") means sex, and 'I' sounds like 愛 (ai, love). So when he says "「今君に'アイ'を捧げる」" [now I offer you my 'love'], he means the letter, not the feeling.
It is not a kind song, and it doesn't pretend to be. "後で泣こうが 俺には関係ない" [if you cry later, that's not my problem], and "朝になれば 消えるだけ" [come morning, I just disappear]. His parting advice is blunt: "傷ついて 何かを学べ" [get hurt and learn something]. Useful words to grab here: 仮面 (mask), 魔法 (magic) and 騙す (to trick).