Capaneus was a mortal with considerable strength, son of Hipponous and Astynome. He was married to Ianeira, with whom he had a son, Sthenelus.
The myth has it that Capaneus was extremely strong and a very capable warrior. However, he was also particularly arrogant, which eventually caused his demise. At one point during the siege of Thebes, he started shouting that he would climb the walls of the city and not even Zeus would be able to stop him. While he was climbing the wall, and as the gods detested anyone who committed hubris, Zeus hurled a thunderbolt against him and instantly killed him.