Boon of Siegecraft (5e Epic Boon)

You have an uncanny knack for bringing down castle walls.

Given access to timber (such as a nearby forest), you can use your downtime to can create a ballista in one day; a mangonel in three days; or a trebuchet in 7 days.
When you are directing the crew of a siege engine to attack a stationary object of Huge size or greater, you can make a bombardment. A siege engine making a bombardment has twice the normal range and long range. In addition if you use your action to fire the siege engine during a bombardment, you can add your proficiency bonus to the attack roll and the attack deals double damage.