It's a shame it doesn't learn Shadow Sneak...
... and why would you want it to survive a strong, super-effective, (likely) STAB move? Not many things can.
Its slow speed means you are most likely going to invest in HP rather than in Speed, and with its double-edged typing, it can abuse its ten resistances/immunities (nine if Rock Head) to find switch-in opportunities, then hit whatever switches in hard... or burn, if you are expecting a Pursuit trap.
Though as a hit-and-run attacker, it will required hazard clearing support.
I thought of Brick Break over EQ (or Bonemerang) because of Dark-types that resist Fire in general, not Rock-types or Steel-types (which are already handled by Flare Blitz if it's not Heatran).