Rather than trying to get Slasher right away, you could head to level 3 and come back later. The guardian for Slasher is rather tough, but depending on the equipment you have found it is possible to defeat him without leveling up outside. That said, there is nothing wrong with heading outside (don't go too far south) if you are having trouble. Some people leave Aleroth to level up before even entering the catacombs.
Early Starter Tips (NON-Spoiler Version)
