Alright well I'll just keep posting in this thread since I'm not limited here, haha!
cc13, I wouldn't ridicule you for that. Some people take tattoos lightly, and can go in and grab some flash and be done with it. That's just not my style, and it doesn't seem to be yours either. Don't be ashamed to do it your way, haha.
There is a decent website for checking out meanings of things, I'll link that at the end, hopefully you'll learn a lot. For example, did you know that dragons are actually koi that made it up Longman Falls and through the Dragon Gate? Too bad probably 3/4 of the people with koi on them have no idea what it means.
In Japanese history, Onis were almost always the bad guys in the story. They were the demon antagonist who the hero always had to kill. An oni, with a club specifically, is a metaphor for an unstoppable force. For me, I made the club special. Like I said it's Diakokten's lucky mallet (it has another name but I can never remember it, Uchide-no-kazuke, or something like that). It can grant the wishes of those who hold it, among many other things. Have you ever read the story of the 1 inch Boy, Issun-Boshi? It's a kids book that I loved when I was younger, and the mallet makes an appearance in that story (granting the wish of the 1 inch boy to become full sized).
On top of all this, since Buddhism started to penetrate Japanese society, onis have taken on an almost gargoyle-like representation. The oni was supposed to scare away evil spirts. That's why things like oni tiles exist. It's a roof tile, which looked like an oni mask, that was put on a lot of temples to keep away ghosts.
Anyhow, so to me the oni and the mallet are kind of like my good luck charm to keep evil away and bring me wealth and goodness. And the part about it being an unstoppable force reminds me to kick my ass and always drive for what I want.
Here is a sight to brush up on Japanese, Chinese, Taoist, and even Buddhist figures and imagery.
Diakokuten
Dragons/Koi