Introduced in Pathfinder's Advanced Class Guide, a Bloodrager is a like a Barbarian except you are very slightly more squishy (being dropped to a d10 Hit Die rather than the barbarian's d12), lose the Barbarian's esoteric rage powers and instead get some minor magic. As Pathfinder is a 3rd Edition derivative, you are noticeably more awesome than a Barbarian thanks to spell casting.
Instead* of rage powers you can choose every level (but most of the worthwhile ones are deep in trees so you'll likely specialize anyways), you select a bloodline like a Sorcerer and get preselected powers and optional feats from that bloodline over 20 levels. Of course, being part-sorcerer, they can also benefit from some of the special options given to them, like the Bloodline Mutations and the Bloodline Familiar.
If you ever wanted to play a guy who gets angry enough to turn into a noodle-armed giant who can spear/punch anyone within 40/50 feet with no setup time and is accompanied by a talking raven-shaped lump of flesh that grew from a lump on his back with little resource investment by level 4? Bloodrager is the class for you!
Bloodragers are Tier 4 or a low tier 3. While they're more versatile in combat than Barbarian, their spellcasting is primarily combat utility and don't gain much more out of combat ability.
*Or should be instead of. Because the ACG was extremely rushed and poorly edited, Paizo printed an archetype that let you trade any bloodrage power you didn't want for TWO rage powers you did at no extra cost! It was immediately banned from all official games.
|The Classes of Pathfinder|
|Core Classes:|| Barbarian - Bard - Cleric - Druid - Fighter - Monk |
Paladin - Ranger - Rogue - Sorcerer - Wizard
| Alchemist - Antipaladin - Cavalier |
Inquisitor - Oracle - Summoner - Witch
| Arcanist - Bloodrager - Brawler - Hunter - Investigator |
Shaman - Skald - Slayer - Swashbuckler - Warpriest
| Kineticist - Medium - Mesmerist |
Occultist - Psychic - Spiritualist
|Ultimate X:||Gunslinger - Magus - Ninja - Samurai - Shifter - Vigilante|