Just for reference, the five elements are Wood, Fire, Earth, Metal, and Water.
If we're going for a purely Eastern approach. But my read on the tradition in the OP was that it was a broader, modern tradition that drew elements from numerous martial traditions with spiritual leanings.
Personally, while I like the idea, I think that it might be better represented by a properly themed character instead. There are numerous approaches and philosophies that could meld spellcasting and swordplay, but some would be distinctly Eastern, some Western, and others beside. For example. my own people's Mau Rakauo would lend itself well to the concept, especially with regards to a Taiaha. But our Tohungas would use the following spirits:
Combat - Man; Detection - Fire; Health - Water; Illusion - Air; Manipulation - Plant.