Post a picture of you encountering a Custodian, i just had to take 3 out, along with 2 shieldbreakers, a soldier, an archon and a sectopod, and it was nerve wrecking (praise the stun mines!).

After i taken em out, the one Custodian on my side (due to the double agent skirmisher perk) was essential in keeping the sectopod busy, and he was very good at it with his good dodging skills and high health.

Here's the pic of the final engagement: https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=1507345195