His loveless marriage at the age of 13 to Margaret, daughter of James I of Scotland, did not help relations with this man's father, with deteriorated to the point that he participated in the Praguerie Rebellion against his father, only to see it fail and be exiled to the province of Dauphine.  
On one occasion this ruler pardoned a murderer in return for the murderer participating as a guinea pig in an operation to remove gallbladder stones. This ruler, upon hearing of his father's severe illness, raced to Rheims to have himself crowned king first instead of his brother and nemesis Charles the Duke of Berry. His loveless marriage at the age of 13 to Margaret, daughter of James I of Scotland, did not help relations with this man's father, with deteriorated to the point that he participated in the Praguerie Rebellion against his father, only to see it fail and be exiled to the province of Dauphine.  He intervened in the War of the Roses by pressuring the Earl of Warwick to oppose Edward IV, only for the plan to backfire and Edward to invade France, while this monarch bribed Edward off with the Treaty of Picquigny.  Known for his political machinations and complicated webs of alliances, this is FTP what ruler, son of Charles VII and King of France from 1461 to 1483 with an arachnid-sounding nickname.
On one occasion this ruler pardoned a murderer in return for the murderer participating as a guinea pig in an operation to remove gallbladder stones.
Louis XI [or Louis the Spider; Louis the Prudent; Louis the Universal Spider]