The 23-year-old ABS-CBN actress believes that the role should be given to someone who is older.
"Personally, Darna is such an iconic role. Alam mo, dream lahat ng babae siguro na maging si Darna, pero, siguro, it's not for me kasi hindi porke't gusto mo yung role, puwede siya sa iyo, e," she told PEP.ph and the press.
"For me, may binabagayan siya, and yung nai-imagine, napipiktyuran ko as Darna is someone who's a bit older than me.
"Someone na parang mas woman. Woman na talaga."
On April 4, Liza sadly announced her decision to withdraw from the role due to a finger bone fracture.
Fans then started lobbying for Kathryn, along with Nadine Lustre and Pia Wurtzbach, to play the iconic Pinay superheroine.
The same thing happened before the role was given to Liza Soberano in 2017.
But Kathryn had her personal choice, "Ewan ko, maybe...hindi ko alam. I don't think it's for me kasi sobrang bigat ng Darna.
"And kapag sinabi mong Darna, parang nai-imagine ko talaga ngayon si Ate Angel."
Angel Locsin was the last actress to play Darna.
Kathryn met with the media before her beauty endorsement event held on April 6, at SM The Block, North Avenue, Quezon City.
Kathryn was just as surprised as everyone when she learned that Liza had to give up the role, but she fully understood the reason behind the decision.
In 2018, Kathryn experienced her first-ever action-driven series in the Kapamilya primetime series La Luna Sangre—the third installment to Angel Locsin's "Moonstone" series, which began with Lobo (2008) and Imortal (2010).
The young Kapamilya actress said, "Alam mo, yung nangyari kay Liza, sobrang totoo yun.
"Kasi kapag kami po sa fight scenes, kunwari madadala ka na sa eksena, so minsan hindi mo na maaalalayan.
"And lalo na sa amin sa taping, hindi rin naman kami binigyan ng, as in, enough time to train para super maging comfortable kasi taon yun, e.
"So, yes, like yun sa La Luna, ang dami mong pasa, ang dami mo talagang sugat. Hindi mo maiiwasan."
What was her worst experience on set?
Kathryn was glad that she only got a few bruises.
"Pasa-pasa. Yun lang naman. Buti walang pilay, walang injuries and all, pero prone talaga, so kailangan talaga mag-ingat.
"And super hirap talaga gumawa ng action film o action teleserye. Ibang hirap siya, ibang level siya nung na-experience ko siya.
"Kaya mas bumilib ako mas lalo kay Ate Angel kasi siya yung kilala sa ganito, e. Hindi siya joke."
Kathryn said she is clueless as to who is the next worthy choice to take on the role of Darna.
She said, "Kung tatanungin nila kung sino yung perfect for the next role, I don't know. Kahit ako, iniisip ko, sino pa ba yung puwede after Ate Angel?
"And hindi ko alam kung sino, so whoever man mapili for the role, kailangan talaga sobrang-sobra paghandaan. Bigyan ng maraming training kasi hindi biro ang Darna...
"Kung sino man ang next, she'll have my full support as a fan of Darna.
"Siya nagre-represent ng woman empowerment sa atin and yeah, we'll support her kung sino man siya.