Beowulf

Obtain all the Heroic Upgrades. Make sure and complete all objectives in while NOT in Carnal mode. Kill enemies using normal combos or during Heroic Storm. Defeating bosses while not in Carnal will net you 7 Heroic points and lasting longer than 2:00 minutes on the Temptress sections will net you 7 points as well. You will need a total of 60 heroic points to fully level up your Heroic skills.

You need a total of 60 points to fully get the max upgrade,and get the achievement. Unfortunately you can not get max carnal and max heroic in the same playthrough as there is not enough upgrades points. Collectables runes help with upgrade points as do boss kills and resisting the women sections, but i could only resist long enough for the heroic when i used a turbo controller. You need a total of 60 points to max out the upgrades. You will need to focus on one type carnal of heroic in a playthrough.

Important things not shared in other guides or the walkthrough:

There are a few parts where you have no choice but to get Carnal Runes, and/or have to go out of your way for a results screen to give Heroic instead:
-The Shadow Warrior objective will give 1 Carnal Rune, no way to avoid it. Carnal use is mandatory.
-On the part right after this, going up a bunch of stairs followed by the bog monsters and the troll in the room that has a bunch of dust appear periodically, you need to go out of your way to farm the bog monsters with Heroic Strikes to make up for the Shadow Warrior section, or you'll get 2 Carnal Runes for the chapter. I included assuming you get 2 Carnal Runes for this chapter for sharing how much wiggle room you have below.
-The Brecca fight, I defeated him without using any Carnal Rage, and got a "Heroic Finish", without getting any Heroic Runes. Unsure if this is normal. I included assuming this always happens to everyone when sharing how much wiggle room you have below.
-Chapter 13, you are forced to get 2 Carnal Runes for the chapter results no matter what. The only fighting is on the temptation part, and if you get 0s in every category for both Carnal and Heroic, the game defaults to giving you 2 Carnal Runes in a tie.

With all of that in-mind - if you last over 2 minutes on all temptations, get all collectible Heroic Runes, and get Heroic rating on all objectives and chapters, and assuming you fail to get the Shadow Warrior chapter runes + don't get any runes from Brecca, you will start Chapter 14 with 67 Heroic Runes, 7 more than needed for the achievement/7 runes of leeway to make mistakes. There is a red flag upgrade box right at the start of Chapter 14 to get the achievement by leveling all Heroic skills to 4, then clicking one of them again to get the final level 5 upgrade.

The main item people seem to have an issue with is the survival for 2:00+ minutes during the temptation segments. A solution for that:

Just keep grabbing one of the women then intentionally letting it fail. Then immediately re-grab, let it fail. With decent timing, you'll never get brought into a mash B escape the woman crawling on you segment.

As a failsafe, you can pause and Load Last Save as you're failing a resist to restart the level.

Rune collectibles occasionally glitch and do not give you upgrade Carnal/Heroic Runes. This happened to me on my Thane + Heroic playthrough. If you don't get upgrade points from collectibles when you expect to, pause and reload your save to restart the level.

Also worth noting, as I didn't see it anywhere: carnal and heroic doesn't start tracking until Chapter 5. Chapters 1-4, you can play however you want and it will not effect any achievement related to carnal/heroic.