Spoiler:

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First off you have 2 be in chapter 4, or around there so you are strong enough to take hits from orcs, and you have access to the castle.
1.draw orcs to the siege ram (entrance to castle)
2.If more than 1 orc came shoot them with a bow or crossbow until there is only 1 (i dont recommend leaving a orc elete)
3. let the orc leave a bit by standing still on the ram
4 run off from the siege ram a good few steps toward the orc
5. open ur invenroy and have ur strength or dex or whatever potion highlighted
6. as the orc starts attacking u (he should take 1 big swing as he runs and 3 small swings as he stops by you) hit ur potion and you should see the STRENGTH +5 or something but the potion reapears
if done right u can continue this over and over again
*Remember that u loose health so run back after a while 2 the ram and health up and do it again if you wish*
*also save before u do it for the first time as u may not time it right! i accually saved the game every 5 times i used the potion so if i used it once without getting it back i justed loaded again*

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