Chakron is the third Star Sage, the guardian of the third and final Star Cure and the owner of the Chakroads in Mario & Luigi: Bowser's Inside Story. He resides atop a cliff in Plack Beach, where he has motionlessly meditated for a thousand years. He is a pink figure with a purple head, a yellow star on top of his head, and pink lips.
In Mario & Luigi: Bowser's Inside Story and Mario & Luigi: Bowser's Inside Story + Bowser Jr.'s Journey, when Bowser first comes across a hidden Chakroad in Cavi Cape, Chakron (who is unseen, only heard as a disembodied voice) introduces Bowser to them and explains them to him, granting him use to them so he can fast-travel across the Mushroom Kingdom. Later on in the game, when Mario and Luigi are searching for the Star Cures in order to stop Fawful, they find Chakron atop his mountain on Plack Beach. He explains that he has frozen in his meditative pose for a thousand years, gathering knowledge from the stars. He offers them the third Star Cure if they can use an attack that would shake the ground and break his pose. During his explanation, Luigi humorously tries to imitate his pose, but falls over. He then tries to tickle Chakron, much to his annoyance.
At first, Mario and Luigi battle him in order to free him from the pose he is frozen in. After three turns, Chakron sighs and disappointingly ends the match. He tells the brothers that there is an attack in "the wood" that will free him of his pose. Mario and Luigi then collect all 10 Attack Pieces in Dimble Wood, learning the Snack Basket Special Attack, and using it in a rematch against Chakron. When the attack is performed successfully, Chakron falls over.
Outside the battle, his statues fall and he voices his displeasure at being knocked onto his back, and rather than relinquishing the Star Cure, he crawls over to the edge of his platform and falls off the cliff. The Bros. and Starlow are surprised and horrified, but Chakron then drops down from the sky unharmed, and assumes a new hand-stand position for meditating. Satisfied with the change, he gives the Mario bros. the last Star Cure and offers to teleport the brothers back to Toad Town. Any time the bros. visit him from that point onward, he will offer them the same instant transport to Toad Town, which presumably works the same way as the Chakroads, although the action is taken off-screen at the secretive Chakron's behest.
Chakron's last appearance is at the ending of the game. After Peach's cake is shown, Chakron reveals in a voice-over that he monitored the player's progress and tells them their ranks, either suggesting the player tries harder next time or congratulating them on getting the highest ranks.
- "How would one describe me? I am...the voice within. I am your consciousness... I am above, and all around. I am all that is you. A consciousness bound to you, as you are to me."
- "Shall we travel together?"
- "Now we travel... With our MIIINDS!"
- "The mists of consciousness part, and two figures emerge."
- "You are unenlightened. That is why you are in a cosmic pickle."
- "I feel nothing! Not even close. Not a wiggle. Not a single astral shimmy. Unless you have an attack that shakes the ground, give it up."
- "And now I go."
- Chakron has the highest stats of all characters in the entire game with 9999 HP, 999 Attack, Defense, and Speed.
- Chakron is also the only boss that doesn't attack Mario and Luigi.
- Chakron has infinite stats, although it is possible to kill him by making 'meaty quake'. The only the one to have highest stat which takes several rounds is Bowser X, who has over 7000 HP.
- Chakron's Star Cure is the only one Mario and Luigi gain outside of Bowser's body.
- With 9,999 HP and 999 POW, DEF and SPEED, Chakron is actually the strongest boss in the game and even the entire Mario & Luigi series. However, Chakron does not attack and cannot be defeated, as his battle will end immediately when a perfect Snack Basket is performed (likewise, Midbus's food items also have similar stats in the game's coding). As such, the title of the game's strongest boss is awarded to Bowser X.
- Other than Scutlet and Dark Star Core, Chakron is the only required boss Mario and Luigi face that does not reappear in The Gauntlet.
- Chakron is the only boss that the player is allowed to flee from, although they cannot flee from Chakron in Mario & Luigi: Bowser's Inside Story + Bowser Jr.'s Journey.