Walls are simple but effective tools best used to protect important buildings and to herd attackers into traps.
Walls are mainly used as an extra protection to the buildings and to slow down the enemy advancement speed. It forces the enemy to take extra time to destroy the walls, allowing other base defenses to deal more damage to them. Walls are pretty fragile at low level, but quickly toughens up after a few upgrades. It’s upgrade cost also ramps up quickly, and it’ll soon cost the players a fortune to upgrade their walls as each level begins to cost millions of Gold while you have hundreds of walls. Walls upgrade immediately and do not require a free builder to do so.
Wolvenfiend is the one Hero whose Fortitude Skill buffs walls. His skill increases their HP by a large amount while also causing them to reflect damage. This is a nice counter to the fact that many Heroes can wipe out large swaths of walls quickly with their skills.