A Zealot uses the Zeal skill as the primary attack skill. As you can see in the graphic to the right, the Zealot has multiple strikes (5 per turn) with enhanced damage and enhanced attack rating. Enhance Zeal with the Fanaticism aura and the damage and attack rating is very high.
Fanaticism aura will increase your attack speed, rating and damage. This is good. And, it will also increase the "hit" damage of any character in your party. This can be very nice for bowzons and barbarians.
Given the skill points available it is possible for a Zealot to have a fully pumped Vengeance skill as well. This skill is excellent for dealing with physical immune monsters. A few hits with Vengeance and Fanaticism and a physical immune is deadski. Because of the five times greater mana/life steal of Zeal, you may find yourself keeping Vengeance as a backup skill and using Zeal for most occasions.
These next three graphics illustrate the standard Zealot build. This represents a level 85 Zealot. As the character advances, extra points can be put into Holy Shield -- to give even better defense.
It is handy to put a point into redemption -- since this will clear the floor of those pesky resurrecting creatures. Soak up the bodies and they can't be brought back to life to battle you further.
It is also handy to put a point into salvation. This will give good resist to other characters such as sorcs. This can be handy when participating in Baal runs. Typically a hammerdin or high level sorc does the bulk of the killing while your character is in the 30 to 75 range. During this period you can run the Salvation and give excellent resist to everyone in your party. A definite contribution.
Here we only put in enough points to get to Fanaticism then max it out.
In this build, one point is put into conviction. This comes at a small price. But Conviction can be an interesting aura. Conviction will lower defense and resistance of creatures. Keep in mind you can only use one aura at a time on a paladin. This means that to use Conviction Fanaticism is turned off. This will cost all of that wonderful enhanced damage and speed. However, there are occasions when Conviction and Vengeance kill significantly faster than Vengeance and Fanaticism.
Because Sacrifice is a synergy to Zeal, you end up with this wonderful special use skill. Try it out on occasion. You'll find it has some special applications.