Due to a general lack of Ceasar’s Legion-related content, getting enough reputation with that can be a daunting task. However, there is a glitch that you can perform by talking to Decanus Severus in Cottonwood Cove that allows you to get infinite XP and Legion reputation, and I’ll show you how to perform it in this guide.

Quick tips before you start:

• Can be used to gain access to the Ceasar’s Legion safehouse. In case you don’t want to play through any of the Legion content, or don’t want to ruin your reputation with the other factions (as Legion quests sometimes require), you can use this exploit to get a Liked reputation with the Legion, get the key from Lucius at The Fort, and then go about your playthrough as you normally would.

This is also a great way to get the Lucky Shades, which are located within the Legion Safehouse.

• Can be done on a non-Legion playthrough. Thanks to the exploit not requiring any progress in the Caesar’s Legion quest line, you can use it on any playthrough.
• Explosives skill of 50 required. In order to make use of this exploit, you’ll need an Explosives skill of 50 or more. This skill can even be temporary, such as from magazines or chems, as the timer on these items does not decay while in dialogue. 
• Use a disguise. In case you have made the Legion hostile, you can use a Legion disguise to get past the guards. Just try to avoid getting too close to any of the dogs or guards.

Performing The Glitch

To perform the glitch, you must first make your way to Cottonwood Cove, located east of Camp Searchlight, by the southern end of the Colorado River.

There is a chance you’ll be approached by a Legion Scout. He’ll ask you about your business. You can either pass a Speech check of 35 for him to let you pass, or you can kill him and his dog with a silent weapon before he manages to speak to you.

Once there, follow the road until you see a set of several red tents and a single, larger, brown tent.

In front of the tent is a person called Decanus Severus. Speak to him.

Select the following dialogue options:

• “I have some questions.”

• “Do you see much action against the NCR?”

• “That is all for now.”

• “I can show you how to disarm the NCR’s mines.”

• “[Explosives 50] The trick is to rush the mine and press the blinking red light.”

You can now repeat this set of dialogue choices infinitely for unlimited Legion reputation and XP.