2-3 Hours: In a large bowl, soak your oxtail bones in clean water to remove excess blood.
6-10 Hours: After those have soaked, add your oxtail bones to a large pot with the onion and cover with water. Bring to a boil and simmer for a minimum of 6 hours. I recommend between 8 and 10 hours. Add water as needed while simmering. The broth should look milky-ish.
Strain the broth into a pot, saving the oxtails. Remove the excess fat from the broth.
Shred the meat off the oxtail bones.
Bring the broth to a light simmer, you should have about 3½ to 4 quarts of broth at this point.
Pierce the eggs with an egg piercer (or a thumbtack). Fill a large pot with enough water to cover your eggs by 1 inch. Bring your water to a boil and carefully add your eggs. Cook for 6-6½ minutes (longer if you don't want your eggs jammy. Once done, immediately add them to an ice bath. Peel carefully.
In a bowl, mix miso paste, gochujang, gochugaru, msg, sesame oil, tamari, vinegar. Grate in the ginger and garlic. Whisk well.
Once the broth is simmering, add in the Kombu strip and then, pour the miso base into a strainer and lower it into the simmering broth. Let it sit for 5 minutes and then hold the strainer and whisk as much of the paste as you can out of the strainer without pouring it in, discard what you can't.
Let the broth simmer for 15 more minutes, it shouldn't reduce or thicken too much. Taste and adjust salt.
While the broth is simmering, in another pot, boil the ramen according to package instructions.
Divide the ramen into 4 bowls and scoop in piping hot broth. Top each bowl with the shredded oxtail, a boiled egg, scallions, salsa macha and Furikake.