The only reason to go Dragon Lord 5 is for the tier-5s, which lock out tier-5 Tempest. IMO there's no point in going dual-wield ranger if you're not taking T5 Tempest because that's where the best stuff is.
Also if this is just a heroic PL, you don't need so many Dark Hunter levels and may be better off with 2H weapons, especially as a half-orc. E.g., Dark Hunter 12 / Dragon Lord 6 / barbarian 2 with T5 DL + level 12 DWS core for +2 crit multiplier +1 crit range. [14-20/x4 falchions, 14-20/x5 Sword of Shadow.] Barbarian splash is for Rage, +10% runspeed, Angry Arms (+20% Strikethrough), and Blood Tribute.
I just threw this together but this is what I was thinking:
Character name: HOrc DL DH (heroics only)
Classes: 12 Dark Hunter, 6 Dragon Lord, 2 Barbarian
Race: Half-Orc· · · · · · ·Alignment: Chaotic Neutral
· · ·Start Tome Final · · ·Incorp:· · ·0% · · ·Displacement:· ·50%
Str:· · 20· · 2 · ·31 · · ·HP:· · · · 971 · · ·AC:· · 10
Dex:· · ·8· · 2 · ·10 · · ·PRR: · · · · 0
Con:· · 16· · 2 · ·18 · · ·MRR: · · · ·15 · · ·+Healing Amp:· · 10
Int:· · ·6· · 2 · · 8 · · ·Dodge: · ·0/25 · · ·-Healing Amp:· · ·0
Wis:· · ·8· · 2 · ·10 · · ·Fort:· · · ·0% · · ·Repair Amp:· · · ·0
Cha:· · 14· · 2 · ·16 · · ·SR:· · · · · 0 · · ·BAB: · · · · · · 25
DR: 3%
Immunities:
Heroic Past Lives
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Past Life: Barbarian
Past Life: Paladin
Special Feats
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Falconry Tree
Inherent Universal Action Point(2)
Vistani Knife Fighter Tree
Class and Feat Selection
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Level Class · · · · · ·Feats
1 · · Dark Hunter(1)· ·Standard: Two Handed Fighting
· · · · · · · · · · · ·Favored Enemy: Favored enemy: Monstrous Humanoid
2 · · Barbarian(1)· · ·
3 · · Barbarian(2)· · ·Standard: Power Attack
4 · · Dark Hunter(2)· ·Strength: +1 Level up
5 · · Dragon Lord(1)· ·Minor Draconic Aura: Thraxata's Instinct
6 · · Dragon Lord(2)· ·Standard: Improved Two Handed Fighting
· · · · · · · · · · · ·Fighter Bonus: Stunning Blow
7 · · Dragon Lord(3)· ·
8 · · Dragon Lord(4)· ·Fighter Bonus: Improved Critical: Slashing Weapons
· · · · · · · · · · · ·Strength: +1 Level up
9 · · Dark Hunter(3)· ·Standard: Improved Sunder
10· · Dragon Lord(5)· ·
11· · Dragon Lord(6)· ·Fighter Bonus: Greater Two Handed Fighting
12· · Dark Hunter(4)· ·Standard: Weapon Focus: Slashing Weapons
· · · · · · · · · · · ·Strength: +1 Level up
13· · Dark Hunter(5)· ·Favored Enemy: Favored enemy: Aberration
14· · Dark Hunter(6)· ·
15· · Dark Hunter(7)· ·Standard: Weapon Specialization: Slashing Weapons
16· · Dark Hunter(8)· ·Strength: +1 Level up
17· · Dark Hunter(9)· ·
18· · Dark Hunter(10) ·Standard: Past Life: Soldier of the Faith
· · · · · · · · · · · ·Favored Enemy: Favored enemy: Human
19· · Dark Hunter(11) ·
20· · Dark Hunter(12) ·Strength: +1 Level up
Enhancements: 80 APs, Universal 2
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Dragon Lord - Points spent: 36
Core1 Draconic Soul: Soul of the Black Dragon
Tier1 Dragon's Protection I
Tier1 Battlefield Tactician I
Tier1 Martial Superiority: Dragon Lord: Martial Superiority: Improved Second Strikes - 3 Ranks
Tier2 Dragon's Protection II
Tier2 Battlefield Tactician II
Tier2 Action Boost: Action Boost: Haste - 3 Ranks
Tier2 Dragonslayer
Tier3 Battlefield Tactician III
Tier3 Dragon's Protection III
Tier3 Dragon's Roar
Tier3 Might or Outburst: Draconic Conviction - 3 Ranks
Tier3 Ability Score I: +1 Strength
Tier4 Dragon's Protection IV
Tier4 Battlefield Tactician IV
Tier4 Untouchable Soul
Tier4 Lead the Charge - 3 Ranks
Tier5 Soul Scales
Tier5 Tactical Commander
Tier5 Improved Dragon's Roar
Tier5 Flight of Kings
Tier5 Conqueror - 2 Ranks
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Deepwood Stalker - Points spent: 24
Core1 Far Shot
Tier1 Stealthy - 3 Ranks
Tier1 Tendon Cut - 2 Ranks
Tier1 Favored Defense - 3 Ranks
Core2 Sneak Attack
Tier2 Action Boost: Melee/Ranged Power Boost - 3 Ranks
Core3 Called Shot: Exposing Strike
Tier3 Thrill of the Hunt - 3 Ranks
Tier3 Favored Hunter - 3 Ranks
Core4 Advanced Sneak Attack
Tier4 Killer - 3 Ranks
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Frenzied Berserker - Points spent: 14
Core1 Die Hard
Tier1 Power Rage - 3 Ranks
Tier1 Athletics - 1 Ranks
Tier2 Blood Tribute - 3 Ranks
Tier2 Angry Arms - 3 Ranks
Tier2 Extra Action Boost - 3 Ranks
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Ravager - Points spent: 4
Core1 Furious Rage
Tier1 Barbarian Power Attack - 3 Ranks
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Vistani Knife Fighter - Points spent: 2
Core1 Knife Expertise
Tier1 Undead Hunter
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Falconry - Points spent: 2
Core1 Summon Falcon: Summon Falcon
Tier1 Hunter's Knowledge
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If you haven't got the +2 Universal AP tome, just drop Falconry. Use whatever racial APs you have as you see fit.
EDIT: at level one, I would take Bleed the Weak, then swap it out once you have DL's Imbue. Of the Draconic options, acid is the least resisted element.