Add drones. Perfect Advanced anti-infintry units that are more effective but expensive than jackals. Upgrades #1: carry ability- Drones can carry a single marine off the ground, instantly kiling him/her. #2: drone engineer: adds a mild healing ability to the drone by giving them plasma cutters, like the drones in Contact Harvest. #3: birthright: drone squads are given a shielded drone leader to command them thus improving thier overall combat abilities.