Notes from author
I made this build focusing only on crystal magic, so you will have a glass defense if you use it. (like dying to 1 backstab or even 2 direct hits for a high damage weapon) but you will do insane amounts of damage with the crystal magic (around 1600 per crystal spear and 2000 for all hits of crystal soulmass, basically instakilling everyone if you get at least 3 hits with crystal soulmass and the hit with crystal spear.). You also have a little bit of poise so you wont get staggered that much,but even so, its just a little bit so be careful. The best use for this build is to get your enemy unprepared, in an invasion in a tight room, like the Cathedral of Anor Londo, Upper Sen's Fortress and so on. If you fuck up ALL your spell casts, just try to poke them to death with the Butterfly Horn since its damage is magical and even if they block, they will still receive a bit of damage.
Use the mushrooms if you invade someone with a fast weapon since said person will probably kill you on the first combo they hit you with.