Disclaimer
These two heroes I'm going to introduce, is just my vision of possible future, just a sketch, a concept. THEY DO NOT EXIST (yet) , neither even planned for future updates.
I will roughly state some parameters and 4 ailities together with some intuition behind this, although giving no exact numbers (damage, stats, etc), even for cooldown and manacost - all of these is TBD.

Name: Chosen One, The
Faction = radiant
Primary attribute = strength
strength growth and agility growth - high-medium
intelligence growth - low
sight range day = less than average
sight range night = slightly more than average

Yan Dawn the ''Chosen One''' one of twelve higher counsellors of the Order. Was a famous strength melee hero long time ago.
He's good utility hero (thanks to Ultimate) and initiator due to perfect infiltration abilities. Can be used as an anti-pick for Bounty Hunter (see below).

Most interesting part of this "guide": the brand new mechanics for 3 out of 4 Chosen One abilities. Let's start with most simple and most boring one:

• Q:Collectivum Scientia
  
• W:Persona Non Grata
  
• E:Immunitas Diplomaticae
  
• R:Quod falsissimum. Ultimate

Description: Passive: the most experienced Codex Custodes hero on map receives a large Intelligence bonus. Global cummulative ability: every Codex Custodes contributes some amount of Int (based on the Q-ability level of course) but only most Experienced one gets it. Grants Codex Custodes status. Active: target (allied/enemy/non Codex Custodes) hero receives whole this bonus for short duration in his own hands.
Lore
The Order is well know for it's Archive - largest library in the world and lots of crossworlds. Only those, who are wise enough to resist such amount of knowledge are granted higher access to this archive.
Ability = Target Unit
Affects = Heroes (except CC status holders)
Key = Q
Bkbblock = Yes
Linkenblock = Yes
Purgeable = No
Mana= Quarter of starting mana pool scaled to half or so
Cooldown= high and un-scaled
Trait1 = Amount - 10/15/18/21 Int should be enough.
Trait2 = Duration - aroung half of minute, may be less
* Note that it can be cast on enemies to trigger their Linken Sphere, or too help Nyx Assassin's "Mana burn"
* Using BKB while having this Active buff should remove it.
* Cannot target CC holders, because they already have a chance to have it passively.
* This keyword I introduced "Codex Custodes" heroes (holders), for the case if there is more than one Chosen One. You know, Rubick for example?
* The most experienced one should be decided by exp. amount, not by level. If two (or more) have the same amount of exp, then none gets the buff

Description: Active: target (enemy/non Codex Custodes) becomes a valid target for their allies and their AoE spells for short duration. This also holds for Creeps/Towers/Fountain (with levels).
Lore
The Order can compromise every single one. It's just a matter of time. Trust noone and be ready for friendly fire.
Ability = Target Unit
Affects = Enemy Heroes (except CC status holders)
Key = W
Bkbblock = Yes
Linkenblock = Yes
Purgeable = Yes
Mana= Quite cheap, but not for strength based hero, however.
Cooldown= Low, scaled down
Trait1 = Valid target for "enemy heroes target spells" (Malefice, Cold Feet etc) and all friendly AoE (Ice Path, Black Hole, RP, Ice Blast etc).
Trait2 = Level 1: friendly Ranged creeps and Catapults attack target on sight. /
Level 2: all friendly creeps attack on sight. /
Level 3: same + towers attack target. /
Level 4: same + Fountain + auras (Hearstopper, Radiance).
* Cannot target CC holders, because the Order doesn't like such things.
* Fourth level upgrade is really game-dependent, and I know it. It was made intentionally.

Description: Active: Chosen becomes immune to the certain types of attacks, mostly by enemy creeps and towers.
Lore
The Order can take. The Order can give. The Order can send an ambassador. An armed ambassador. Why not?
Ability = No Target
Affects = Self
Key = E
Bkbblock = No
Linkenblock = No
Purgeable = Yes
Duration = Low (3/4/5/5) ?
Mana= Low cost
Cooldown= Low, scaled up
Trait1 = Damage from auras doesnt counts toward you (Heartstopper, Radiance) since the first level.
Trait2 = Level 1: enemy Ranged creeps and Catapults ignore you for duration of cast. /
Level 2: all enemy creeps ignore you. /
Level 3: same + enemy towers. /
Level 4: same + enemy Fountain + AoE (Ice Path, Black Hole, RP, Ice Blast) doest deal damage to you.
* First two levels are not so usefull, however give you some benefits.

. Ultimate
Description: Active: Target unit becomes as valueable prey as an illusion. It gives exactly 0 gold coins in case of death.
Lore
IT'S A FAKE!
Ability = Target Unit
Affects = Allied Heroes (except CC status holders), Allied Units, Roshan, Allied Towers
Key = R
Bkbblock = Yes
Linkenblock = Yes
Purgeable = No
Duration = 10-15, scaleable
Mana= High for strength based hero
Cooldown= Null
Trait1 = Target generates 0 gold bounty on death
Trait2 = Remove BH's Track's gold bounty, keeping other bonus (speed, true sight).
* Use it wisely.
* Instead of denying unit
* On carrier's death game should play the illusion death animation. Kill/Death/Assists however counts normally.
* Doesn't trigger Battle Hunger removal.
* Doesn't heal Bloodseeker from Blood Bath

Name: Chosen Too, The
Faction = dire
Primary attribute = agility
strength growth and agility growth - high-medium
intelligence growth - low
sight range day = less than average
sight range night = slightly more than average

Yen Dusk the ''Chosen Too''' one of twelve higher counsellors of the Order. Was a famous agility melee hero long time ago.
He's good utility hero (thanks to Ultimate) and initiator due to perfect infiltration abilities. Can be used as an anti-pick for Bounty Hunter (see below).

Yep, this is exactly the same guy as before (Abilities too!) except three parameters:

• Name and position in Hero table (you can see both of them in one All Pick game, for example)
  
• Primary attribute: One is Strength-based hero when Too is Agility-based hero
  
• Side of conflict: One works for Radiant, when his collegue Too supports Dire.

That's why I need this keyword Codex Custodes status. These two guys should not use abilities on each other.

Haven't you seen another Chosen around here? He must be Intelligence hero, I think. His name starts with "R" and ends with "ubick".

The main idea behind these two heroes was to add something pair-wired into Dota2. We already saw the "Three spirits" update, but they are different heroes, by game mechanics, only the Lore unites them. I was looking for something "Meepo"-like, yet not so hard to play.
I think it will be a good counter to some heroes like BH and BS. Moreover, the very first ability, is something easy (passive Int bonus) yet new to the Dota. It depends on heroes experience, so the winner get everything. Still you have a way to not spend a points if you are not the only Chosen here and you are far behind him in EXP.

I highly appreciate any help in improving this "guide".
This includes language, abilities balance and so on.

I do not even hope of getting these heroes into the Dota2, at least not in next year, they still working on old heroes, like Goblin Miner and Oracle, but one day there will be no more old heroes to include, and Valve employee may found a guide with a thousands of millions Upvotes and say "hmm, looks interesting, why dont we add a Workshop for Heroes too".

Thanks for reading.