(Add or change : Version 1.1)

■The system starts

An Equipment item "Eternal League Of NightingAle" is added in The Frozen Hearth Cellar.
When your follower equips with it, the teleport system starts. When he unequips, the system ends.
A message is displayed in each case.
 The system starts : "...Have you contracted with Nocturnal...really?"
 The system ends : "...I feel like someone grin"

Can't be turned the system start in combat. You have to prepare before the combat.

■About the teleport system

In combat, your follower casts the Shout. player and follower go into "standby mode".

1)"Shadow step"(Player)
when you draw the weapon and sneak without moving, if your  follower  equips with a bow, a crossbow, or "Nightingale Illusion blade", you can teleport to your follower. 
"Shadow step"(Player) needs follower's magicka costs. If your follower doesn't have enough magicka, you can't teleport.
Rank up improves the magicka costs.

When you are in a dangerous situation like you are surrounded by enemies or have few health, You can escape instantly.
You can use "Shadow step" for about 10 seconds even after the end of the combat. 

2)"Shadow step"(Follower)
When your follower shots an arrow, if his target enemy equips with a bow, a crossbow, a staff or a spell, he teleport to his target enemy. 
After he has teleported, he casts conjuration spell "Nightingale Illusion blade"(Bound weapon). his combat style changes to melee form, and he sticks to his target  enemy. The melee form duration is random, but it lasts up to about 20 seconds.
"Shadow step"(Follower) has no costs.

* "Nightingale Illusion blade"(Bound weapon)
this weapon has low damage rate, but it can bind a enemy by enchant "Stagger".
Rank up improves "Nightingale Illusion blade".

3)Follower and player's combination
if you teleport while your follower teleports, you can approach a ranged enemy in an instant. it is strong counter tactics against ranged enemys.
ranged enemys like Archer, Caster, Dragon Priest etc lose the distance advantage. On the other hand, if you use combination teleport, you take more attacking chances. 

4)Rank up
Your follower's skill value improves the teleporting performance.

Rank1 [No conditions]
"Shadow step"(Player) : Magicka costs 80% (You can only use it once in a row.)
"Nightingale Illusion blade" :  Damage(4) Swing speeds(0.95)

Rank2 [Archery(25)]
"Shadow step"(Player) : Magicka costs 50% (You can use it twice in a row.)
"Nightingale Illusion blade" :  Damage(5) Swing speeds(1.0)

Rank3 [Archery(50)] 
"Shadow step"(Player) : Magicka costs 33% (You can use it 3 times in a row.)
"Nightingale Illusion blade" :  Damage(7) Swing speeds(1.05) *Visual update!

Rank4 [Archery(75)]
"Shadow step"(Player) : Magicka costs 25% (You can use it 4 times in a row.)
"Nightingale Illusion blade" :  Damage(9) Swing speeds(1.1)

■Tips

(1)This teleport system is not simply a linear enhancement like Increased damage or status value. Depending on how you use it, this system can be used both offensively and defensively and the magnitude of the benefit change. This system requires your brain. 
(2)Your followers should have only one bow or crossbow. In that case, this teleport system works perfectly. 
(3)Your favorite archer follower can combat in the screen. It is very important, don’t you think? That was the reason I made this MOD. 

■Notes

(1)This MOD has no changed vanilla data, and needs no requirements.
(2)You must not duplicate "Eternal League Of NightingAle". It causes a bug.
(3)This MOD's follower AI have priority 100(max).All other combat override packages do not work.
(4)This MOD is made with game balance in mind. But it may depend on your Skyrim.
(5)When player teleports, if there is underwater on that route, the graphics may look strange. In that case, please go into the water once. The graphic will be fixed. 

■Uninstall / Update this MOD

[Uninstall]
After 1 minutes from the combat and your follower unequips with "Eternal League Of NightingAle",uninstall this MOD.
1 minute is because magic effects in combat is cut off.

[Update]
Overwrite.