Endo: Drop sources, locations, and probabilities

Tips

There are many ways to get Endo in Warframe, but my recommendation for optimal efficiency would be to try one of these missions (in this order):

• Mars/Tyana Pass : It's a Defense mission (level 25-30). The item is dropped on rotation A (36.25%).
• Deimos/Nex : It's a Exterminate mission (level 55-60). Probability to get it: 39.39%.
• Deimos/Effervo : It's a Assassination mission (level 55-60). Probability to get it: 39.39%.
• Deimos/Armatus : It's a Disruption mission (level 55-60). The item is dropped on rotations A(18.18%), B (10.00%) and C (17.50%).
• Zariman/Halako Perimeter : It's a Exterminate mission (level 50-55). Probability to get it: 35.56%.

These recommendations are based on the usual missions lengths, and the probability of getting the resource dropped.
Only mission rewards are listed here. Enemy drops are not taken into consideration, there might be more efficient options available in some cases.

Missions with a Chance to Get Endo as a Reward

Warframe Rotations Explained

• Defense: One reward every 3 waves, following this pattern: AABC.
  So, rotation A reward at 3 and 6 waves, B after 9 waves and C for 12 waves.
  Then it starts all over again.
• Survival: One reward every 5 minutes, following this pattern: AABC.
  Rotation A at 5 and 10 minutes, B at 15 minutes, C at 20 minutes, etc. Then it starts all over again (25min is rotation A).
• Interception: One reward each time 100% control is reached, following this pattern: AABC.
  Rotation A for the first two times, rotation B for the third and rotation C after four.
  Then it restarts from the beginning (5th round is rotation A).
• Excavation: One reward after each excavator successfully completed, following this pattern: AABC.
  Rotation A for the first two excavators, rotation B for the third and rotation C after four.
  Then it restarts from the beginning (5th excavator is rotation A).
• Caches: Number of resource caches opened:
   - Rotation A: one.
   - Rotation B: two.
   - Rotation C: all three.
  
• Rush: Number of transports destroyed:
   - Rotation A: one.
   - Rotation B: two.
   - Rotation C: all three.
  
• (Elite) Sanctuary Onslaught: One reward every 2 zones, following this pattern: AABC.
  So, zone 2 and 4 give rotation A rewards, 6 gives B and 8 gives C.
  Then it restarts from A, etc.
• Infested Salvage: One reward after each successful decryption, following this pattern: AABC.
  
• Disruption: It's a bit complicated for disruptions, as it depends on the current round.
  Here is a table clarifying what you get for each round:

  Round	Conduits
  	1	2	3	4
  1	A	A	A	B
  2	A	A	B	B
  3	A	B	B	C
  4+	B	B	C	C

  
  So, rotation C is only available at round 3 for 4 conduits defended. Or at round 4 and more for a minimum of 3 conduits defended.
• Spy: One rotation level gained per vault unlocked.
  First vault is rotation A, two vaults is rotation B, all three vaults unlocked is rotation C.

Mobs Dropping Endo

Endo can be dropped by most ennemies in Warframe. You should probably consider this as your primary farm source.

---