A rarely used way to say, "What the hell or What the fuck." No one really uses that phrase anymore, it expired after a few days in Canada of hardly catching on in 2000. Though there are people who are trying to bring the phrase back, it is a losing battle. Actually, the battle has been lost. People tend to say "What in God's name" now instead due to the religious movement in 2004.
Hartley, the phrase, "What the blood" will never catch on.
"What the blood" does not exist, Hartley.
When Hartley says "What the blood" the world seems like an unfriendly place. Don't say it, Hartley.