Malcolm Colcord forced Box to use his powers to make an army of Sentinels, which he used to take over Weapon X from Jackson by attacking his hideout and years later to wipe out the X-Men. Due to Colcord's constant demands for more Sentinels, Box became exhausted, causing Sentinel production to decrease. So, Box created Bot to carry some of the workload.
19 years later, Bot had transformed himself to the new Master Mold, imprisoning Box inside his newly transformed shell and took control over the Sentinel army. Bot's actions lead to Box's death.