Yes, he is. Having recently received my copy of the Manual for Spiritual Warfare, I’ve been meaning to write a short review on it. But I’m late to the party and Russell Shaw over at OSV has already done the heavy lifting for you.
Attacks from the Enemy can become even more intense as you progress in sanctity. This is why we see a multiplicity of examples from the lives of the Saints where the Devil is enraged whenever anyone becomes close to God, and he works even harder — and more overtly — to bring about spiritual destruction. Consider the Cure of Ars (St. John Vianney) as just one example. Other examples abound.
In other words, no one is immune to these attacks, which means that we must be vigilant, and receive the sacraments of Reconciliation and Eucharist with frequency. A good regular (daily) examination of conscience is also helpful. And, as St. Padre Pio would say, a rosary in the right hands is a very powerful weapon. A rosary is an irritation to the Devil even if it stays in your pocket the entire day.