As you’d imagine, go speak to Jahlzahn in North Shroud. Then to Gerolt. Then to Rowena and back to Gerolt. You then end up heading off to Swiftperch to an NPC just outside called Remon.
Talk to Remon twice. Once to get the information and secondly to pay 200 soldiery tomes to get your first Mahatma applied to your weapon. You can use your Zodiac Glass to check whether your Mahatma shows any sense of assertion. If you’ve lost your glass, Remon tells you how you can get another one.