Who's This? Two-Face's ancestor from the Revolutionary War and page 31 of Who's Who vol.XIII (I'm kidding about the first part of that).
How you could have heard of him: Time travel stories gave him a little more to do, specifically in Swamp Thing #86 and Time Masters #4, but he hasn't actually been seen since 1990.
Example story: Tomahawk #75 (1961) by France Ed Herron and Fred Ray
Who else? Having covered Lord Satanis adequately in a Reign of the Supermen article, I'm just going to skip to the next volume of Who's Who.