The Battles of the Third Age (BOTTA) mod is a mod for The Battle for Middle Earth - The Rise of the Witch King. This mod tends to follow the lore of books and films along with bringing the realism in the gameplay, and generally concentrates of the happenings in the Third age of Middle Earth
Grond is not available in the Siege Works anymore. I felt that it is not the right system for it because it was too simple. Grond can be summoned from the spellbook now and last 4 minutes.