Notes from author
Since DSR has weapon matchmaking, you'll want to make sure that your weapons don't go over +5. This, however, does not apply to armor, so upgrade that as far as possible. To get Great Combustion without a +10 Pyromancy Flame, ruining your weapon level permanently, get a phantom in your world that has one. If not, just use another spell. The Falchion should also not go over +5, meaning that a +0 Fire Falchion is as far as you can go. You can invade levels 6-28, along with weapon levels 0-11, so early areas like the Burg, Parish, and the Depths should be suitable for invasions. Have fun stomping on new people, this is truly the definition of Chaotic Evil.