To obtain a Firm Arrowhead, you need to find and kill Hilichurls Shooters at any level. Upon eliminating these standard enemies, they have a chance to drop Firm Arrowheads.
You can get these from Hilichurls; however, they do have to be Hillichurl Shooters. No matter the Element of the Shooter, it will drop Firm Arrowheads. Luckily you'll find Hilichurl Shooters near Hilichurls and often encountered in the larger camps.
The fastest way to get around is to use the Waypoints, kill everything in sight, and then move on. The two images below are where you can find Hilichurls in both Mondstadt and Liyue.
Just click on them to enlarge them.
Thanks to Genshin Impact Interactive Map!
- Type: Common Ascension Material
Firm Arrowhead is used for the following Character Ascensions.
Each Common Ascension Material has three tiers, these are the next tiers after Firm Arrowhead.