About the command:
This command is the first command I have put in the database and is untested
The villager buys 1 emerald for each of the trades, and sells each the following items:
1 pickaxe, renamed "Op tool", that is very good
1 blue colored chestplate, renamed deep ocean chestplate, that is also very good
2 potions:
1 Notch potion, which has all the good effects, and is regular
and 1 Herobrine potion, which has almost all the bad effects (no instant damage, so it tortures rather than kills), and is a splash potion