Goblin Slayer

Goblin Slayer (Japanese: ゴブリンスレイヤー Hepburn: Goburin Sureiyā) is a Japanese Dark Fantasy Light Novel series written by Kumo Kagyu and illustrated by Noboru Kannatuki., which began serialization in 2016. It has two manga series, three Drama CD's, a side-story named Year One (both in manga and novel format) and a 13-episode TV anime series released in 2018. It started as a sort-of online textboard roleplay combined with ASCII artwork, which was later rewritten into a novel format and sent to some writing contests; it was picked uo by the GA Bunko publishing label, and then one thing led to another...

The series itself begins in a terrible note, story-wise. A rookie party formed by a Fighter, a Female Wizard, a Warrior and a Priestess, all of them at quite the low power/experience rank, decided to go into a nest of goblins to try wiping them out and rescuing their prisoners. However, due to their lack of preparation, the group is horrifyingly overwhelmed: Warrior is literally torn apart, Fighter is captured and gangraped, Wizard is fatally wounded, and Priestess is all but indefense against the goblins themselves. Suddenly, however, a stranger decked in full-body armor shows up and saves Priestess, helps her rescue the still-living Fighter, gives Wizard a Mercy Kill at her request and completely annhilates all the Goblins and Hobgoblins there...

Priestess learns that the man is the Goblin Slayer, an adventurer whose one and only goal in life is to erradicate all kinds of Goblins. Feeling that she owes him her life and that she still wants to go further in adventures, she becomes Goblin Slayer's partner and keeps travelling with him. Eventually, the two form a more stable party with other travelers (a High-Elf Archer, a Dwarf, and a Lizard Priest) and keep on fighting, exploring the dangerous world, and exterminating Goblins and other menaces...

Tropes used in Goblin Slayer include:

Attack of the 50-Foot Whatever: One of the easiest taks for adventures consists in taking on giant rats.
Blood Knight: Goblin Slayer commments that after so much time killing goblins he may as well doing it because it feels good to fight and kill them.
Fan Disservice: The Wizard's chest bouncing? Good. Bouncing because she is struggling with a goblin that seeks to beat her up and then rape her? Not so good.
The Faceless: In-universe, most people never saw Goblin Slayer's face since he never removes his helmet. At the end of Volume 1,Priestess asks if she can see his face and the title character removes his helmet without any problem in public.
Human Shield: At the climax of Volume 1, a group of goblins uses human hostages as shields, knowing humans aren't likely to kill other humans to reach an enemy.
Oblivious to Love: In-universe, this is the witch's opinion about both Goblin Slayer and Priestess.
Older Than They Look: The High Elf Archer looks like a young adult at best, but it is actually 2000 years old.
Revenge: Goblin Slayer's initial motivation to kill goblins was to avenge his family. As time goes on,however, it takes the shape of a psychological obsession(he only does that,even knowning there may be more important jobs which may save as many or even more lives as killing goblins do), and he says to Guild Girl in Volume 1 he is beginning to enjoy it.
Skewed Priorities: Goblin Slayer dismisses a quest to save the world from an army of demons because goblins attacking villages are somehow more important. However, soon he lets it slips why he does that: there's so many Evil Overlords appearing and then being defeated that he feels there's no consequences if he ignores such tasks in favour of hunting goblins, an activity that attracts well less attention from adventurers, downplaying the trope.
Supporting Protagonist: Most of what happens in the story is followed through the eyes of Priestess instead of the title character.
The Comically Serious: The title character is prone to give straight-forward Mathematician's Answers, is almost completely single-minded in killing goblins and often answers with a straight "no" or "yes". The result is this.
The World Is Always Doomed: In Volume 1, Goblin Slayer offhands mentions a demon lord have awakened ten years ago when it's told one is doing the same thing now, basically saying there's no point for him to care about such threats when they're always happening and are always stopped by someone else.
Zerg Rush: The goblins are generally weak, but they attack in numbers to compensate for their individual weakness.