Predecessor Builds > GRIM.exe > GRIM carry [v0.17.3]

From Neft, Cold and Laken latest builds

As ADC, you should build Grim for attack damage (AD), not ability power (AP)
The best build is the one shown above

Crest:

The most reliable crest is Liberator, although you can go Typhoon and Pacifier if you prefer

Last item:

Caustica is a solid last item for the pen, if you don't need pen you can go World Breaker for dmg, hp and tenacity