This is heresy, of course, having Dark Angels and Space Wolves work together, but purely from a tournament perspective, consider the following battle group:
-2 x Iron Priests with TWC mount (one has Wulfen Stone Relic)
-Wolkin formation with 4 packs of 10 combined into an “Alpha Pack” (or 40 wolves total)
-Allied Xenos Inquisitor with Rad Grenades, PML(1) for Divination, and Liber Heresius Relic
Azrael makes the entire unit Fearless, gives every model a 4++, and uses the Rapid Maneuver WL Trait to add +3″ to run and charge ranges. He also chips in, where necessary, with his own S6 AP3 attacks on the charge and 2+/4++, once he catches up with everyone else.
The Xenos Inquisitor lowers the enemy Toughness by -1 on the first round of close combat (thanks to Rad grenades), gives re-rolls to Hit via Prescience, and most importantly, gives the unit Scout for a free 12″ move before the game begin (Liber Heresius Relic grants this if he passes a Ld test successfully). He also can use his Psyk-out Grenades to reduce any enemy Daemons or Psykers to I1 on any turn that he and his unit charge them, so great against things like Hive Tyrants, Daemon Princes, or amped up Astartes Librarians.
Iron Priests are the Beatsticks (of course), with 11 x S10 Attacks on the charge, plus 6W protected by 2+/4++ and T5. The IP with the Wulfen Stone also gives the entire unit Furious Charge.
Finally, the 40 Fenrisian Wolves form a giant “Alpha Pack” that benefits from all these buffs and can stretch across pretty much the entire board for massive board control as they advance toward the enemy. Between ignoring difficult/dangerous terrain and the +3″ to their Run from Azrael, they can move up 16 – 21″ on turn 1 (using a few wolves to “conga line” back to Azrael to keep him in coherency, despite his slower movement). They also give the whole unit Monster Hunter, which obviously helps against those types of opponents in close combat.
With 40 T4 Fearless wounds protected by a 4++, plus another 6W on the IPs protected by 2+/4++, they can absorb lots of shooting cheaply and set up for a turn 2 charge. On the charge (or if the enemy charges them and they use Counterattack), they get 160 x S5 attacks (or 120 attacks if they multi-charge, which is highly likely), all striking at an enemy with -1T (so against MEQs, they would be wounding on 2+s and even against T6 MCs they would be wounding on re-rollable 4+s, thanks to Monster Hunter). Also, with 12″ movement and Azrael’s +3″ to charging, they have a VERY solid chance of making it successfully.
Once the Fenrisian Wolves are in combat, they are the perfect “expendable” tarpit unit, with Fearless and 4++ and only costing you a few points more than a Guardsman per model. This is particularly ideal against something like a massed Tau gun line, since the Wolves could potentially tie up multiple Crisis, Pathfinder, Fire Warrior, Riptide, Stormsurge, Broadside units all at once, preventing them from shooting at the rest of your army.