Five-Man Band: They're very clearly trying to be one, although they may have missed their marks by a little. For example, Otayellow is obviously supposed to be The Big Guy, although he's not so much strong as he is just plain fat.
Sixth Ranger: In Danball Senki W, we are introduced to a pair of American Otarangers - Otasilver, a blonde bombshell who likes to partially unzip her jumpsuit to show off her cleavage, and Otagold, a Token Minority black guy whose helmet is too small to fit on his head.
"Super Sentai" Stance: They like to do this at every possible opportunity - even when riding an escalator. It tends to get increasingly silly each time. Plus Otayellow keeps screwing it up.
Parental Abandonment: His family is nowhere to be seen in either the present or flashbacks. Highlighted in a heartwrenching scene at the airport where he was alone while other kids had their family seeing them off.
Missing Mom: Oozora Haruka, a scientist working with the company Omegadyne on an system called "Adam & Eve." She and Hiro are eventually reunited, and she ultimately decides to leave to join up with our heroes.
A mysterious LBX engineer who created Killer Droid, an anti-LBX weapon. Covered in bandages and confined to a wheelchair, its suggested he suffered major burns all across his body. Although his true identity was originally thought to be Hiyama Ren, aka Lex, it turns out to be his little sister, Hiyama Mami instead.
Paper-Thin Disguise: He's not fooling anyone. Everyone and their uncle from the first series (as well as his employers) recognize him as Lex. Needless to say, her true identity was a shocker to pretty much everyone, in-universe and out.
The name of a terrorist organisation, or at least its masked spokesman, with the ability to "Brainjack" or seize control of numerous LBXs at once to cause chaos. It was all the work of Yamano Junichiro of all people, trying to put a stop to Omega Dyne's conspiracy by turning the LBXs they've distributed into their most obvious threat.
The head of Omega Dyne, world authority of LBX distribution. He brought in Dr Mummy to the company, backing his work and the creation of Killer Droids to further Alferd Gardyne's agenda. He didn't live to see the result.
Oozora Hiro's Missing Mom, who's been away from home and working on a massive AI in the UK. Turns out it's the very same AIs that are used to manipulate the Pparadise Kill Sat, and by the time our heroes find out, it may be too late...