Double Crossbow is a technology in Age of Empires II HD: Rise of the Rajas that is unique to the Khmer and can be researched at the Castle once the Imperial Age is reached. Once researched, it makes Ballista Elephants and Scorpions fire two projectiles instead of just one.
To offset the power a little bit, however, the secondary projectile has a slight cone spread and does less damage than the primary one.
The secondary projectile of Scorpions and Ballista Elephants deals 6 pierce damage and 3 bonus damage against Elephants. The secondary projectile of Heavy Scorpions deals 12 pierce damage and 4 bonus damage against Elephants. The secondary projectile of Ballista Elephants benefits from Chemistry but the secondary projectile of Scorpions does not.
Double Crossbow further bolsters the strength of Ballista Elephants and the Khmer's already impeccable Scorpions (+1 range due to their team bonus and access to Siege Engineers) against mass infantry.
Scorpions and Ballista Elephants with Double Crossbow are effective in large groups, as they can devastate large areas (comparatively, this puts the Khmer Scorpions at the same level as Ethiopian, Celtic, and Chinese Scorpions).
Double crossbow is a set of crossbows with double bows, enabling the user to fire two arrows almost simultaneously. According to reliefs from 12th and early 13th centuries, Khmer people were known to employ double crossbows as their weapons. This practice was borrowed from China, who installed those weapons at the siege and defense of fortresses. The Khmer however, put these arms on the back of war elephants.
- Schliesinger, Joachim. 2011. "Ethnic Groups of Cambodia Vol 1: Introduction and Overview" (p. 169). White Lotus, Bangkok.