The Kalevipoeg is the national epic of Estonia. Much like its close cousin, the Finnish Kalevala, it has been pieced together from folk songs, tales and ballads by an ambitious 19th century poet. Friedrich Reinhold Kreutzwald had a lot less material to work from than Elias Lönnrot, and the first version of his epic couldn't even be published due to censorship (there are some pretty risky details in there) - but he still managed to compile a twenty-song long continuous story. The epic is now available in English both in verse and in prose format.
So if the hero is not exactly a likable fellow, why should anyone read this epic?
Well, here are some reasons I found:
1. The first song. It tells us the story of Kalevipoeg's mother, and her cosmic courtship by the Sun, Moon, Water, Fire, and other supernatural suitors, before Kalev comes along. There are various versions of this tale collected from Estonia; one of them tells of the creation of the Milky Way.
2. Wizards. There are many different kinds of wizards in the world of the epic. There are word-wizards, wind-wizards, death-wizards, and my personal favorites, salt-sorcerers. They all have their own spells, magic rites, and personalities.
3. The tiny episode where Kalevipoeg gives a spiky coat to a naked hedgehog. Because: naked hedgehog.
4. The description of Hell (Kalevipoeg visits the underworld multiple times) from where three girls are rescued. Hell itself is a series of chambers - according to folktale tradition we see chambers of iron, copper, silver, gold... aaaand then we go on to silk, velvet, and lace. The rescued girls take some time to loot the latter rooms before they return to the world of the living. I would too. Also, the three girls get their own story after they are rescued, and they generally fare better than other women in the epic. (The second descent into the underworld is also entertaining - it reads like a well-designed Dungeons & Dragons adventure, with caves and traps and everything.)
5. Song 16 tells us the story of Kalevipoeg's mythic journey to the end of the world in the far North. There are whirlpools, whales, islands of fire, and half-canine men - all in all, pretty much everything that makes a mythic voyage a mythic voyage.
6. Olev. There are other heroes around Kalevipoeg (Alev, Sulev and Olev), and Olev is by far the most likable. He spends his time building splendid cities for people. When Kalevipoeg realizes that he is not really a good king (duh), he gives up his throne for Olev. Best choice he makes in the entire epic.
7. The language. Much like the Kalevala, the Kalevipoeg also has an enchanting, repetitive, alliterative rhythm that lulls you into reading it. I imagine it would be even more enthralling if sung.