If you rely on Lightning Sentry, immune monsters can only be killed if you use an Infinity.

Make sure you have decent survivability, a Call to Arms can help you immensely. Playing solo: The build is great for soloing the game. Not an effective ladder starter as good gear is quite expensive.Not a good fit for Hardcore as it’s survivability is not that great.Solo Baal or Chaos runs are doable within 4 minutes.Can quickly solo the whole game in top tier items.Very fast run speed and mobility, especially if you can also teleport via an Enigma.Trap Assassins, just like Javazons, are great members of parties due to their immense lightning damage and fast mob clear speed. A solo Chaos or Baal run in high-end gear will take you less than 4 minutes. Runspeed and mobility can be incredible if you cast Burst of Speed, especially while you wear an Enigma. Once they have an Infinity on their Merc, even lightning immune monsters can be killed by the Lightning Sentries, so the whole game can quickly be soloed. Trapsins are great for MF-ing, as with high faster casting rate they can get to Bosses quickly, and they can wear magic find gear with minimal compromises. As with other Assassin builds, their survivability is not their greatest strength, so I’m not suggesting the build for hardcore. Boss kills will also be fairly fast, but Uber Tristram can cause you trouble. Traps deal immense damage, so in endgame gear you will clear mobs in no time. You can start your ladder season with a Trapper, just don’t expect extraordinary performance, unless you are in a party that has Conviction aura or a necromancer with the Lower Resists curse. The playstyle is relaxing, once you put down the traps they will do their job and take care of enemy monsters. The build is quite expensive, for optimal performance you will need an Enigma in order to be able to move fast.

It relies mainly on the attacking skill Lightning Sentry, but Death Sentry or Fire Blast can also be utilized to kill Lightning Immune monsters.

The Trapsin (Trapper Assassin) is one of the strongest and most popular caster builds in Diablo 2 currently.

Best pvp assassin build diablo 2