Event Horizon is a "Peak-Eating" Limiter - it's a clipper with an optional soft-clip circuit. By truncating waveforms short of where the DAC would go into clipping, you can get VERY transparent loudness increases; unlike most limiters, Event Horizon does this with ZERO pumping, ZERO transient or frequency artifacts, and with ZERO latency. It may not let you be louder than the latest flavor of the month mastering limiter, but within its range of operation, you WILL get a natural sound.
Its output is what comes into it only louder. If you push it too hard, it will tell you in no uncertain terms that this is no longer the right tool for the job.