Ok, I drew this in two sessions: 1 was the general sketch and shading, the second was the detail.

The 6 notches on the top are how many greater demons he's killed, the symbols along the main body says "Inadvertant" in Angelic script, (read right to left), the 2nd level is the 7 elements (from left to right) Fire, Earth, Air, Water, Spirit, Life and Death. The last tier is taken partially from Alchemlemical symbols and is read right to left as "Day and night, I shall hunt the evils and of this world in the name of God."