Added in patch 3.27, Bloodline Ascendancies add new options to the Ascendancy system.
Your character can have one classic Ascendancy (such as Trickster) and one Bloodline Ascendancy (such as Animist Farrul)
After completing the Eternal Labyrinth, you will have a pool of eight shared Ascendancy points, typically allowing you to select four notables. (The Ascendant on the Scion class has different options).
Details on how to access Bloodlines are based on incomplete information from GGG and are subject to change.
Allocating and Respeccing Bloodline Ascendancies
To allocate points into a Bloodline Ascendancy, you will need to defeat the corresponding boss. Locations of each boss are listed.
You can respec the Bloodline Ascendancy points in the same way you would respec a classic Ascendancy point - either five respec points from quests, five Regret Orbs, or by paying a gold cost to Faustus.
Tip: Under character level 83, Faustus' gold respec costs are reasonable. Above level 90 they are unreasonably high and you'll want to use Regrets most of the time. Between these levels both choices are reasonable.
List Of Bloodlines
Animist Farrul
Farrul, First of the Plains is found by first encountering a Farric Tiger Alpha in an Einhar mission in a map, defeating it, and then sacrificing it at Einhar's Menagerie. Farrul is the easiest Bloodlines boss to defeat.
Farrul's bloodline mostly offers nodes that would interest a 'lead from the front' hybrid minion and direct attack or spell character build.
Herald Lycia
Lycia is found in the deepest floors of the Forbidden Sanctum. To encounter her you will need to find a Forbidden Tome, a somewhat rare drop that any monster in maps can award. You'll get one to get started late in Act 10.
Her bloodline offers a very powerful Herald node, as well as elemental conversion and profane ground options.
Delirious Imposter (Tangmazu)
Unlocking Tangmazu's bloodline requires completing the Simulacrum, the Delirium capstone encounter.
It offers tremendous defense or offense... at a huge cost.
Lich Catarina
Catarina's bloodline is unlocked by defeating her in her hideout, accessed via a Syndicate Medallion. These are uncommon drops from high level Betrayal safehouses.
Her bloodline offers new options for minion builds, especially those that cast their own spells as well as conjuring minions.
Primordial Knight Aul
Aul the Crystal King's bloodline is unlocked by defeating him in the Delve mines.
Aul cannot be encountered before depth 111, is staggeringly rare until depth 200, rare from 201 to 500, and uncommon deeper than 500.
This bloodline offers all classes access to a weaker alternative to the Trickster and Juggernaut exclusive nodes that prevent action speed reductions.
Runesmith Olroth
Olroth, Origin of the Fall is uncommonly encountered in level 81+ logbooks when the player elects to investigate a Knights of the Sun site.
His bloodline offers new methods to scale or benefit from Ward.
King In The Mists
King In The Mists is encountered by using an Audience with the King, an item found occasionally in Ritual reward windows.
His bloodline is very niche. Most players won't want it... but it allows you to do things that are otherwise impossible, for a price.
Oshabi
Oshabi, Avatar of the Grove is accessed by using a Sacred Blossom in the map device. These Blossoms are uncommon drops from Harvest bosses.
Her bloodline offers very different choices based upon Azmeri magic.
The Trialmaster
The Trialmaster is encountered very rarely in Ultimatum encounters in tier 14+ maps, and can also be guaranteed with an Ultimatum Scarab of Duelling. These are quite rare drops.
His bloodline encourages using Vaal skills and/or corrupted items.
Breachlord
No image version of this Ascendancy was released by GGG. It is unlocked by defeating It That Was Esh and It That Was Tul in a Hive Colony.
The two nodes named after former Breach bosses incorporated into the Hive each have three lines of text, but can be worth taking even if one of them isn't active on your build. For example, Tul of the Blizzard is a strong node even if you are unwilling to wear Cryonic Rings.
Note that this is NOT symmetric - there is a cold node and a lightning node, but no comparable fire, physical or chaos nodes.
Esh Of The Storm (2 points):
Your Hits ignore Enemy Monster Lightning Resistances if all Equipped Rings are Synaptic Rings. (Synaptic Rings are a new Breach-exclusive item base) +2 to Level of all Lightning Skill Gems if at least 4 Foulborn Unique Items are Equipped +30 to Intelligence
Tul Of The Blizzard (2 points):
Your Hits ignore Enemy Monster Cold Resistances if all Equipped Rings are Cryonic Rings. (Cryonic Rings are a new Breach-exclusive item base) +2 to Level of all Cold Skill Gems if at least 4 Foulborn Unique Items are Equipped 30% increased Freeze Duration on Enemies
Otherworldly Appendages (2 points):
Take 15% less Lightning Damage with at least one Eshgraft grafted to you Take 15% less Cold Damage with at least one Tulgraft grafted to you Take 15% less Fire Damage with at least one Xophgraft grafted to you Take 15% less Physical Damage with at least one Uulgraft grafted to you Nearby Enemies take 100% increased Damage from Graft Skills
Of particular note:
Tul Of The Blizzard and the Foulborn version of Tulborn that replaces the cold damage to spells with up to 4 gem levels to cold spells have tremendous synergy. This can easily allow players to reach the 'soft cap' of gem level 30, beyond which gem level scaling is still powerful but has reduced effects.
Additionally, any character with only three good choices in the main Ascendancy can benefit from Otherworldly Appendages and an Uulgraft.