Sword Summoner

You can summon red or green magic sabres using your spellcasting modifier 

spellcasting

You can choose two cantrips from the warlock spell list(except eldritch blast) along with two spells to know, Int is your spellcasting modifier. Your spells and cantrips known goes up as you level up.

Preparing spells

You can have as many spells prepared as your Int modifier+prof+your rogue level

spell slot chart

1st 2nd 3rd 4th
3rd 3 3 2 — — —
4th 3 4 3 — — —
5th 3 4 3 — — —
6th 3 4 3 — — —
7th 3 5 4 2 — —
8th 3 6 4 2 — —
9th 3 6 4 2 — —
10th 4 7 4 3 — —
11th 4 8 4 3 — —
12th 4 8 4 3 — —
13th 4 9 4 3 2 —
14th 4 10 4 3 2 —
15th 4 10 4 3 2 —
16th 4 11 4 3 3 —
17th 4 11 4 3 3 —
18th 4 11 4 3 3 —
19th 4 12 4 3 3 1
20th 4 13 4 3 3 1

 

Dagger barrage

As a bonus action and an expense of a 1st level spell slot, you can attack with a range attack with a spectral sword( range 60/120) you summon. When making an attack roll you add your Int modifier and it does piercing damage equal to your sneak attack bonus.

Spectral Rampage

You can use your Dagger barrage as an action at the expense of a level 3 spell slot You can ise this feature twice per short rest

Distortion Blast

You can expend a 3rd level spell slot and make three Spectral sword attacks. You can only use this feature once per long rest

Great GodSlayer

You summon a giant spectral sabre at the expense of a spell slot(atleast 1) and make an attack of one spectral sword per each spell slot(if you used two spell slots you roll 20d6s). You can only use thsi feature once per day and if it doesnt finish the battle you have lvl1 and goes up a level every five turns until combat is finished.