D&D 5e: Ranger 5 / Rogue 3

A few months back, Ban and I were invited and we joined a 5e campaign. The GM was a player in Ban's 5e campaign that had already concluded. PCs started at level 5.

Even during Ban's campaign, Ban helped me to brainstorm a range character that could deal lots of damage to single targets. So I started with ranger and aimed for Hunter archetype and the Colossus Slayer feature at level 3.

However, a few things made me changed my mind:

• The feat Sharpshooter. Even if I don't use its first feature (-5 to attack, +10 to damage), the other 2 features sufficiently make this a good feat. However, taking this means forgoing the ability score increase (ASI) at level 4. This problem is addressed in the next point.
• GM allows the choice of Variant Human race. Since this race starts with a feat of your choice, I do not need to forgo ASI to take up Sharpshooter. However, one obvious disadvantage of this race is the lack of Darkvision. Our wizard (my darling Ban haha) refuses to spend a spell slot each day to cast an 8-hour long Darkvision on my ranger. This issue is addressed in the next point.
• GM allows the choice of Gloomstalker archetype from the book "Xanathar's Guide to Everything*". This archetype comes with the feature Umbral Sight: " At 3rd level, you gain darkvision out to a range of 60 feet. If you already have darkvision from your race, its range increases by 30 feet. "

(*Honestly, I would have disallowed the use of this book. Stuff here are overpowering.)

This meant that if I wanted Sharpshooter, ASI and Darkvision, I had to forgo the Hunter archetype and its Colossus Slayer feature. Once I accepted that, I had to rethink my strategy.

With Ban and his brother's help, I reshaped my ranger's strategy to be one where I deal nova damage on my first turn, which should be a surprise round because I will be in stealth beforehand, and hope to kill at least one enemy before the proper rounds begin. This is making use of the Gloomstalker's feature Dread Ambusher.

So, on my first turn, if I hit (with advantage, since I'm hidden), the damage will be:

(x2 because of Extra Attack ranger feature)

Longbow: 1d8 +4 (x2)

Hunter's Mark: 1d6 (x2)

Sharpshooter: 10 (x2)

Dread Ambusher: 2d8 + 4

Total: 4d8 + 2d6 + 32

Average: 57

Ban said that typically combat doesn't last more than 4 rounds and so I compared this build with the Hunter-Colossus Slayer + Sharpshooter + Wood Elf  Hunter ranger build (thereby forgoing ASI). Assuming 4 combat rounds and factoring the probability of hitting, the expected total damage are:

Gloomstalker: 107

Hunter-Colossus Slayer: 94

This was quite a drastic change in playstyle for me because I prefer consistency, not 1st round nova damage, but I believed I've been doing quite well thus far.

I've planned out ahead for the next 3 levels, estimating that the campaign ends at level 8, eventhough the GM hopes to get us to level 10 (which I think it's a little ambitious but I hope it's true though haha). So to enhance this 1st-turn nova damage build, I plan to choose the following:

(1) PC level 6: Level 1 Rogue

This is to get Sneak Attack. Yes, more damage!

(2) PC level 7: Level 2 Rogue

Cunning Action enables me to hide, as a bonus action, and so enable me to attack with advantage, which means I'm more likely to utilise the first feature of Sharpshooter i.e. -5atk -10 dmg

(3) PC level 8: Level 3 Rogue

The archetype Assassin has this feature, Assassinate, that further enhances the 1st-turn nova damage. Dread Ambusher adds bonus to intiative equals to Wisdom modifier and hence my ranger has a total bonus of 7 due to 18 Dex and 16 Wis. This increases the chance of me taking my turn before most, if not all, enemies if I do not have a surprise round.

So the level 8 build will be Gloomstalker 5 + Assassin 3. The 1st-turn nova damage, if I hit, will be:

Longbow: 1d8 +4 (x2)

Hunter's Mark: 1d6 (x2)

Sharpshooter: 10 (x2)

Dread Ambusher: 2d8 + 4

Sneak Attack: 2d6

Total: 4d8 + 4d6 + 32

These should be critical hit due to Assassinate feature, which means rolling the dice twice. Our GM, however, wanted to ensure that this dramatic moment has significant impact since rolling dice twice could, say, produce all 1s. So he ruled that critical hit damage consists of rolled dice + max dice + modifiers. This means the above translate to:

Total: 4d8 + 4d6 + 88

Average: 120