Modding is extremely easy. It's a matter of making a text file with only a few lines. Here, let me get you started:
#modname "Cheat Mod"
#description "This mod makes the Great Sage really GREAT"
#selectmonster 251
#name "Super Sage"
#descr "This sage is super duper f33r his !337 sk!77z."
#ap 60
#mapmove 12
#hp 500
#prot 25
#str 20
#enc 1
#att 20
#def 20
#prec 20
#gcost 0
#eyes 3
#heal
#end
Just add or remove new command lines between the "#selectmonster" and the "#end" lines. Change the number after #selectmonster 251 to mod a different unit. Use Ctrl+I while looking at a unit to find other units to mod.
Save those "#..." lines to a file using Notepad and save it as some filename ending in ".dm", like "Cheat.dm". Then load the game and use the mod selection option. Then create a new god using the super dude.
Etc. Watch out for any other GREAT sages you meet during play...
PvK