... assuming you meant OVERlord.
But even then, if all he's got is a Warscythe and a ResOrb, that should only come out to 130 points.
Is he packing something else that you haven't listed? (if not, I'd say the first thing you should get with with the left over points is a Sempiternal Weave).
If you're gonna use Destroyers, just stick to a unit of 5 regular variety. They'll be able to remove one
TAC squad of marines every turn.
You might not have models for them, but would you be opposed to using Crypteks? (most people just use conversions anyway, as the official model
GW makes is garbage).
If you'd be alright with it, I'd suggest you make a Royal Court of 1 Harbinger of Despair (with Veil of Darkness and Nightmare Shroud) and 2 Harbingers of the Storm. For 120 points, this unit will reliably get first turn-first blood, as long as your opponent is using vehicles (yes, even against Landraiders).
Some of the other Harbingers might be worth considering, too. Particular attention should be paid to the Destruction type.