Well then, you're at the endgame now. You first steps into the Blood Magic's endgame are the Tier 5 Blood Altar and the Archmages Blood Orb.
To get the Tier 5 Altar however, you need to have 4 beacons first. Once you have these, and have built the Tier 5 Blood Altar, you can try to get a Demon Blood Shard.

For this you will need to do some demon summoning. This in turn requires six Arcane Pedestals (from Blood Magic) and an Arcane Plinth.
With those, and six elemental essences of your choice (Aether, Incendium, Terrae, Aquasalus, Tenebrae or Sanctus), you can summon an Elemental, which has a Chance to drop a Demon Blood Shard.

Use the Demon Blood Shard to craft yourself an Archmage Orb Frame, together with some other rather exotic components, and then put it in your Tier 5 Altar.
With some time, and a lot of LP, you will get an Archmages Blood Orb from this.

The problem is, Blood Magic still has a sixth tier. And this one's even harder.
For this you will need to perform the Convocation Of The Damned ritual. Make sure to put this as far away from your base as possible, preferably in another dimension altogether. The Mining Dimension tends to be a good option.
This ritual not only requires a lot of LP to start, but it also requires quite a few essences.
I would recommend looking up which ones should be put where, seeing as this would be too long to put in the guide book.

Once the ritual starts, there is no stopping it. Demons will invade whereever you built the ritual, and build a town there.
To get the required Crystal Clusters for the Tier 6 Altar, you will need to kill them, and get Soul and Life Shards.
This will then finally be enough to finish Blood Magic, for now.