inaccessible place, impregnable position, steep place, sharp eyes
險 centers on a place that is hard to reach or attack: a steep, inaccessible, or impregnable location. The sense of sharp eyes extends this idea to a keen, penetrating gaze that is difficult to evade.
險 combines ⻖ (a mound or hill) with 僉, which likely contributes the sound and the idea of sharpness or steepness. Together they suggest a steep, dangerous hill or a place that is hard to access.
The left side ⻖ is a hill, and the right side 僉 looks like a sharp, pointed structure. Picture a steep hill with a sharp, impregnable fortress on top: an inaccessible place that requires sharp eyes to spot.
For ケン, imagine a steep, inaccessible mountain pass that only Ken can climb: Ken -> ケン, and his sharp eyes find the way.