Lal took in Colonnello as her student at COMSUBIN before they became Arcobaleno. According to Reborn, Lal, at first, didn't accept Colonnello as her student because he was younger than her, and thus kept saying that he was weak and couldn't do it; however, some event made her agree to take him as her student. They grow close to each other after that eventually turned into romantic, since whenever he's around; she always blushes, though she's sometimes annoyed by him because he always said that she "has to act more womanly".
In the future, his death really shocked Lal and she even keeps his pacifier and headband and sometimes looks at her photo with Colonnello. Colonnello also returns her feelings the same, often teasing her and even participating in the Arcobaleno battle to free her from the Arcobaleno curse. Colonnello also interrupted the birth of the Arcobaleno and attempted to replace Lal to save her from the Arcobaleno curse; however, despite his good intentions, Lal lost her Rain Flame and became the holder of a corrupted Arcobaleno Pacifier, as well as being inflicted with several scars. During the Curse of the Rainbow Arc, when Colonnello transforms back into his adult self, Lal calls him "the shameless newbie soldier that hits on his instructor." After the battle, he eventually able to propose her to marry him and they are engaged, though because of an argument, they must postpone their wedding ceremony.
Lal acknowledges Reborn's power, and even admits that he is the strongest Arcobaleno; however, she is sometimes irritated by him because he always knows what Lal will do or what she is thinking. Reborn also sees Lal as an important comrade, and, in the future, he always gives her many suggestions, mostly about her condition because of the Non Tri-Ni-Set, to which Lal always protests. He also sometimes wants her to change her personality because he states that she's too serious and that she hates jokes.