Elden Ring PC | Dealing with the Lion Guardian near the Limgrave Tower Bridge site of grace on NG

He can't reach you when you stand in this passageway. Use whatever items you can craft. I used a Gravity Stone Fan at the end.

Drops:
1428 runes
1x Somber Smithing Stone [1]
1x Beast Blood
2x Old Fang

Lion Guardian
"Lion Guardian is an Enemy in Elden Ring. Lion Guardians are aggressive beasts that serve as guard animals, and fight with their sharp claws and a blade attached to their right arm. Once slain, they do not respawn."
https://eldenring.wiki.fextralife.com/Lion+Guardian

Gravity Stone Fan
"Gravity Stone Fan is a Consumable Item in Elden Ring. Most Consumables grant various effects such as restorative properties for recovering HP, removing certain negative status effects or applying temporary buffs and debuffs, while others can be thrown at enemies to deal damage."
https://eldenring.wiki.fextralife.com/Gravity+Stone+Fan

First runs on a new character are always the hardest.