To be a tank, you must be Pure STR. That means you have to use the STR based weapon, blade.
Don't think Force would be really helpful for self healing. The HP pots can do a better job. Unless you want to resurrect others.
Cold would be good for the phy def buffs and it's imbue can freeze mobs.
A STR character will need fire to support it's lack of Mag def. Fire buff can increase phy dmg too. Fire imbue is highest in dmg.
To sum it up, you should use a blade.
