Khaman moves stealthily towards the open field (stealthily) so Ronin hasn't any idea where Khaman might be.

Ronin backs away as far as he can from the forest edge, again readying his crossbow.  He will attempt to make his foe cross a field to come at him.

ok...

What's Ronin's Dexterity modifier, and how far away is he from the edge of the wooded area?

Ah, nevermind.

Khaman strides out from the trees, and it's almost like he blinks into existence. His eyes bright with some strange form of humor, he says "Go on then. Fire away."

As soon as he sees the target Ronin let's fly from his crossbow....Attack of opportunity

Attack: 26 Damage: 10

(is that your turn?)

Note the arena is 300X300, in 1/3 of each  terrain, so I figure from the edge of the wood to my location is now 150 give or take...Sharpshooter means NO disadvantage for long range...

Uh, how do you have a +13 to hit? Prof bonus is +6, dex I presume is not +7. Also, fighters don't get expertise.

Assuming you have a +8 to hit, your hit would be 14, which is below my AC. 

+6 profficiency.  + 5 dex.  +2 Archery fighting style.

You used your ASI right?  I mean I don't expect any character here not to be maxed on there main ability.  And fighters have the most so Ronin is loaded with feats.

Oh, fighting style. That makes sense ig.

Khaman uses uncanny dodge (reaction) to halve the damage to 4 piercing. 

Khaman grins at this one's futile attempt to slay him. "Nice try, weakling."

He (bonus action) dashes towards Ronin (60 ft. movement) and dodges (action)

Ronin smiles, calls upon his inner strength.

1st USe of fighting spirit to gain advantage canceling the disadvantage.  Will make 4 attacks all with sharpshooter.

Attack: 11 Damage: Unable to parse dice roll.

Attack: 20 Damage: 23

Attack: 27 Damage: 19

Attack: 16 Damage: 24

(Hang on One sec, let me get the popcorn.)

ah.

I see. 47 damage... ig.

I should be able to reach you by now by (bonus action) dashing.

current hp: 100(rogue)++3con(60)+tough(40)-47= 193 hp.

I will attack w. scimitar (rogue class gives shortsword but I prefer scimitar if that's ok, same damage and everything)

Attack: 24 Damage: 48

gross, isn't it? The amount of terrible damage one sneak attack can do?

Unless I am missing something, shouldnt 200 HP - 47dmg be 153 HP left?

HP   224   +15 temp  -48 = 191  (Fighter, +3 con, tough, and the 15 temp for fighting spirit)

Ronin grunts at the attack, and again calls upon his fighting spirit......

Attack: 21 Damage: 25

Attack: 26 Damage: 20

Attack: 28 Damage: 21

Attack: 12 Damage: 17

All attacks with advantage for fighting spirit and using Sharpshooter for -5 hit  +10 damage.  No penalty due to melee range due to crossbow expert.

more to come....

Action surge for another turn......in this case for the 4th attack at advantage he will change it to two attacks without advanvantage....using Rapid Strike

Attack: 22 Damage: 20

Attack: 24 Damage: 24

Attack: 15 Damage: 20

the two without advantage

Attack: 26 Damage: 24

Attack: 16 Damage: 16