Lich's range units consist of Acolytes, Occultists, and Warlocks. They have very high damage output but have very short ranged compared to other ranged units such as the archer, unless on the garrison wall, where they have (as any unit on the wall) unlimited range.
Their high damage and the fact that they are easy to replace (they share most of the lich's melee units properties on the subject) means they are a good choice to attack walls, specially if their Undead trait is taken into consideration (Undead units excel at plundering resources when attacking city walls).
They can be buffed by Gazul’s passives and other heroes have abilities/passives that synergies with them.
Undead units are not affected by morale. When defeated, they cannot fall injured, but once you have built a Hospital, defeated Undead garrison troops have a chance of being resurrected. Undead units are avaricious by nature, and they excel at plundering resources when attacking city walls.
All
Light Armor
This Unit receive massive damage from enemy troops.
All
Vengeful Spirit
Upon dying, curse the nearest enemy unit, preventing it from attacking and moving. Does not affect Massive units.
Silver & Gold
Gloomy Burial
Upon dying, diminish the morale of nearby enemy troops.