To get the Hugr-Rip you just need to advance the first mission in this DLC.
To fully upgrade it you will need to gather special resources. There are 5 different powers you can absorb and each of those has 2 bonus upgrades once you absorb it. Each upgrade will cost 5 silica and 20 of whatever material is unique to that power. There is also an upgrade to get a second Hugr bar, as well as some versatility upgrades to give you some base stat boosts. NOTE: all upgrades are required, including unlocking all versatility upgrades
Power of Muspelheim:
Has 2 upgrades, 5 silica and 20 Magma Blood each (found by fighting and looting Muspel, Brann and Ash-Bringer will always yield some)
Power of the Raven:
Has 2 upgrades, 5 silica and 20 Giant feather each (found by killing giant birds as you explore the map, you will get 2 feathers per bird you kill)
Power of Rebirth:
Has 2 upgrades, 5 silica and 20 Living Spark each (found by fighting and looting Muspel, Flame Keepers will always yield some)
Power of Jotuheim:
Has 2 upgrades, 5 silica and 20 Jotun Seidr each (found by killing Jotun, Jotnar-Djevelen will aways yield some)
Power of Winter:
Has 2 upgrades, 5 silica and 20 Frozen Blood each (found by killing Jotun, Jotnar-Guld will aways yield some)
Hugr Reaver:
10 silica upgrade to get a second Hugr bar (no other upgrades after that)
Versatility: (note you need to do a world event to unlock this)
You get access to this Power up by doing the world event "The Ballad of Kraka and Skavi" in the Svaladal region. The start point is on the highest mountain in the eastern area. Talk to Skavi and fly up to get his item, after collecting it fly back to him and answer anyway you like. This will unlock all the other Embers. (credit to LitaOsiris who commented where to find this world event)
There are 4 bonuses that you can switch back and forth from once you unlock them, no matter which one you unlock, it will cost 1, then, 2, then 3, and again 3 Ember of Muspelheim.
You can loot one Ember of Muspelheim from the floating red rocks throughout the DLC area, but to get the achievement you will need to collect all of them to unlock all the bonuses. (Use the Power of the raven to fly up to them)
There are 4 Embers in the Gullnamar region,
There are 2 Embers in the Svaladal region, and
There are 3 Embers in the Vangrinn region
In total you will need for this achievement:
60 silica
40 Magma Blood
40 Giant Feather
40 Living Spark
40 Jotun Seidr
40 Frozen Blood
9 Ember of Muspelheim
(since this a new dlc please let me know if i got anything wrong)