I Can Only Fight Enemies I Can See is an achievement/trophy in Deus Ex: Mankind Divided. It is awarded for completing a hack that uses "fog security" to obscure the nodes, without the help of a Reveal Software to remove the fog.
This achievement is easiest to obtain by hacking an object with a low security level. Most hacking challenges that use fog security have multiple possible routes to take from the initial node, meaning that you have to guess which one will bring you to the final green node(s). It is advisable to save before attempting the hack, so that if you choose the wrong route, you can simply reload and go down the correct one. As long as you reach the green node before the timer runs out (or without being detected at all), you will be awarded with the achievement.
Otherwise, you can capture all nodes that are visible so that you simultaneously travel down all possible routes, guaranteeing you will reach the green one(s). However, this will obviously increase your chance of detection as you are capturing more nodes.
- The achievement title is a paraphrase of a line ("I can only go after the enemies I see...") by Adam Jensen near the beginning of the game.