Hive missions are exclusive to the infested planet
Eris, which is unlocked by defeated Tyl Regor on Titania, Uranus.
There are five Hive missions on Eris, but for the purpose of this achievement, you can complete any mission five times. Assuming you have to start from the beginning of Eris, complete Acanth, Brugia, and Cyath. Your choice now is to either play
Lepis (28-30) or continue on through Cosis to reach
Candiru (26-28). I found Candiru significantly easier than Lepis.
Hive missions involve taking down a number of hives. Spoiler alert. When you reach a hive, you must destroy tumor nodes before you are able to damage the hive. Upon destruction, it will unleash a status effect on the rest of the map. Each hive will do one of three things:
- Freezing the ship, which halves your shields
- Toxin clouds, which appear as a red haze and do decent damage as long as you stand inside
- Magnetic fields that strip your energy, which appear as a different red field.
By the end of the mission, all three will be present. There's also the chance that some areas will be exposed to space, where you'll take constant damage.
As you'll be facing infested, the best weapons to take will be Slash, Electricity, Toxin, and Heat to make Slash/Corrosive/Heat. If you can only take one of those elements, Corrosive is better for the big enemies.
I've found that for most people, it's only really solo capable with a well built tank and at least one heavy hitting weapon. I did it at what I considered a minimum co-op with Nyx Prime and Dread, and a friend with Rhino Prime and Galatine, all level 30 with double capacity.