Every medieval themed map and mod seems to have obsessive archer syndrome. The walls are lined with several dozen firing their infinite supply upon your poor, helpless self. Generally you only have four options:
The first is to tank the oncoming rain as well as you can and rush the archers at close range. You lose half your hp and your progress in the arrow rain is impeded by knockback. Not fun.
The second is to snipe them at long range. You don't interact with them in any way, thus defeating their purpose, and painstakingly pick each one off from a tree. Not fun.
The third is to kite them around. Kiting implies the presence of poor AI and is nothing more than hit-retreat. Not fun.
The fourth is to run away. Why make a fort I can't take down? Not fun.
I play with damage immunity off, less health regen and massively decreased armor. An archer wall means certain death. No sort of arrow, not even the touted "armor piercing" bodkin, ever dealt that much damage against a guy in gothic plate. Bodkins were cheap and sometimes got into eye slits, but they weren't magical armor melters.
Hence this mod. Arrows deal significantly decreased damage (defaults to half, can get lower or higher) and don't knock you back. Additional effects, such as poison or fire, apply fully, because that part makes sense. You can configure which projectiles and which shooters are whitelisted. By default Taoism's projectiles are whitelisted because they are fair and balanced (tm).