when you go up agents the other factions you need to bring the best elements to make it quick and painless.

Elements agents factions
1:Corrosive / Electricity X Toxin best agents armored enemy's like the grineer and corrupted grineer
2:Magnetic / Electricity X Cold best agents Shield enemy's like the courps and robots
3:Viral / Toxin X Cold best agents flesh enemy's like some of the courps and grineer
4:Gas / Toxin X Heat best agents the infested
5:Electricity this one is the best to kill robots

these are the best elements to help kill your enemy's faster so make you sure you can get [Vicious Frost], [Volcanic Edge], [Virulent Scourge], and [Voltaic Strike].

Happy killing Tenno ;)