Class Level Summary: Ranger (23), Tempest (5), Horizon Walker (11), Rogue (1)
Race: Human
Alignment: Any
Starting abilities: Str (8), Dex (18), Con (10), Wis (14), Int (14), Cha (8)

Ending abilities: Str (8), Dex (34), Con (10), Wis (14), Int (14), Cha (8)

Ending stats without unique/legendary items unbuffed and without iouns/legendary bonuses: 64ab with two light blade weapons, 63 with ranged weapon (-2 against non enemies), 81 AC in +8gear and haste, DoE DC 49

This is just theorycrafting. The values aren't exactly great at level 40 without additional bonuses. Getting legendary levels and legendary bonuses is a must.

Build options:

• Greater Two-Weapon Defense: +2 AC for a price of one pre-epic feat (Toughness = -40HP)
• Armor Skin: +2 AC for a price of one epic feat (-1DEX = -1AC -1AB -1DoE), but if this is taken then Greater Two-Weapon Defense should be taken at epic level as well so the summary would be +3 AC for a price of -1AB and -1DoE
• Monk instead of Rogue: removes dependancy on a padded armor as with robe you get +1AC from monk, option is also to continue with monk at levels 41+ which would increase AC in robe further, price is a loss of Sneak Attack 1d6, trapfinding ability and possibility to dip into rogue skills (OL, DT) for a price of 1point; personally I would not take more monk at additional levels as that means less DC of DoE, so the only advantage is easier gearing really
• different Terrain Masteries; immunity to death spells can be obtained from potion so perhaps 3/- DR or Blind Fight would be better option; similarly Water Breathing is currently not that needed as it has low DC, but that might change in future
• taking Tempest and Horizon Walker pre-epic: this would give +4 fort for a price of -1 fort and -1 reflex, additionally it would allow to swap last favored enemy for epic feat (Bane of Enemies) which would significantly boost levelling and gave you 1 extra epic feat (Epic Prowess / Two Weapon Rend / Blinding Speed); but the build have only a few favored enemies and this might make it even more specialized than it already is and you would have to use feat exchange vouchers to swap dungeons effectively, current selection fits Kuo Toa, Haunted Rock, Minotaur Maze, Spiders Forest (partially), Treacherous Forest (partially)

Build Upgrades:

• Assassin instead of Rogue: basically no extra cost, stealth skills are useful and you should max them anyway, main advantage is the Poison Use feat, additional benefit is access to True Strike spell
• Beastfolk race would give +2 Dex which means +1AC +1AB and +1 DoE for a price of 2 WIS and 40 skill points from human. It is also missing the free feat, but gives Lightning Reflexes that the build needs for Tempest so that evens out. 2 less WIS means loss of 3rd and 4th level of spells, where the only really useful spell is Aid I would say. Alternatively you can take only 18 Dex which gives you same starting stats +2 extra points you can put into Con (+40HP, +1 fort) or Str (+1 dmg, weight limit increase). Or maybe 19 Dex, 14 Con and 9 Str which means +40 HP, +1 fort and +1 epic feat (ie. +2AC from Armor Skin) as you would no longer need the last Greater Dexterity.