Who can you help to become thane of Falkreath on Skyrim?

In Skyrim, you can help the character known as "Dengeir of Stuhn" become the Thane of Falkreath. To do this, you must complete a series of quests for the people of Falkreath, which typically involves assisting locals with various tasks. Once you have gained enough favor and completed the necessary quests, you can then speak to the Jarl to be granted the title of Thane for Dengeir. Additionally, helping Dengeir's rival, "Maven Black-Briar," will prevent him from becoming Thane if you choose to support her instead.